French Onion Sourdough Focaccia

Few things smell more comforting than the cosy flavour of French onion soup - slow-cooked onions, melty cheese, and a whisper of herbs - now imagine that wrapped in the soft, pillowy crumb of an airy sourdough focaccia bread recipe. French Onion Sourdough Focaccia combines everything we love about long-fermented doughs and savoury bakes: deep caramelised sweetness, crisp golden edges, and that unmistakable sourdough depth.

It's the kind of bake that instantly transports your kitchen to its happiest, warmest place.

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Ingredient Notes

• Strong Bread Flour. Use a good quality strong bread flour with at least 12% protein content. The higher protein supports gluten development and gives the focaccia dough its soft, stretchy texture. All-purpose flour will work in a pinch, but may result in a less airy sourdough focaccia, and you may need to reduce the amount of water. 
• Water. Hydration is key for a soft, open crumb. Use lukewarm water to help your dough mix smoothly and encourage an even dough rise.
• Active Sourdough Starter. A bubbly sourdough starter at 100% hydration is your natural yeast. It should be recently fed and active, ideally doubling in size within 4-6 hours. This replaces the need for instant yeast or active dry yeast and contributes both flavour and lift to the dough.
• Salt. A small amount (5g) balances flavour and strengthens the gluten network. Pink Himalayan salt or fine sea salt both work well.
• Olive Oil. Extra virgin olive oil gives the dough its rich flavour and crisp edges. You'll use it both in the dough and for dimpling the toppings.
• Caramelised Onions. The heart of this recipe. Slice the onions thinly and cook them low and slow in butter with salt, pepper, and a splash of balsamic vinegar. The result is deeply sweet, slow-cooked onions that bring the cosy flavour of French onion soup into your bread.
• Gruyère or Comté Cheese. For that signature melty cheese top. Gruyere cheese melts beautifully without becoming greasy and pairs perfectly with onions. Brie cheese can also be used for a creamier finish.
• Fresh Herbs. Rosemary or thyme adds brightness and aroma. Strip the leaves from the stems to scatter across the surface of the dough.

Recipe Tips

Making great focaccia is equal parts technique and patience. After many loaves of sourdough bread and plenty of test bakes, here's what truly makes the difference:

• Fermentolyse First: Combine your strong sourdough starter, flour, and water before adding salt or oil. Let it rest for about an hour - this fermentolyse step jumpstarts gluten development and makes the dough easier to handle later.
• Oil Goes in by Hand: Add your olive oil after the dough rest, and squish it in by hand before turning on the stand mixer. Adding it too soon can cause the dough to split.

• Knead Until Smooth: Use a dough hook attachment and knead on medium speed for 10-12 minutes until the dough gathers around the hook and feels elastic. You want a very wet dough - that's what gives you an airy sourdough focaccia bread.
• Coil Folds for Strength: Every 30 minutes during the bulk fermentation, perform a set of coil folds with wet hands. This strengthens the gluten network without knocking out the air.
• Watch the Bulk, Not the Clock: Bulk fermentation should take around 4-6 hours depending on the temperature of your kitchen. Look for a dough that's risen 50%, bubbly at the edges, and full of life.

• Cold Fermentation for Flavour: Resting the dough overnight (or up to 24 hours) in the fridge improves flavour and texture. This slower fermentation also makes shaping easier the next morning.
• Use the Right Tray. A rimmed baking sheet or high-sided baking pan (approx. 23×23 cm) helps the dough rise evenly and makes shaping easy. It also allows you to cover the dough with a damp cloth or plastic wrap without it touching the surface.

• Second Rise Matters: Once transferred to your baking dish the next day, let the dough rest for 1-2 hours in a warm spot. You'll know it's ready when the surface of the dough looks puffy and blistered.
• Dimple Deeply: Use oiled fingers to press the caramelised onions and cubed cheese deep into the dough. This prevents toppings from burning and traps pockets of air for that classic focaccia look. This si especailly important with toppings that caramelise well, like in this or our Plum and Gorgonzola Sourdough Focaccia.

• Bake Until Deep Golden Brown: A preheated oven (200°C / 400°F) and 20-25 minutes of baking gives you a crisp top and soft interior. Cool on a wire rack for at least 20 minutes before slicing - it helps set the crumb and avoids a gummy texture.

Serving Suggestions

French Onion Sourdough Focaccia is incredibly versatile - a delicious bread that stands proudly on its own or as part of a meal.

• With Soup: Serve warm alongside your favourite soups for the ultimate comfort pairing.
• With Salad: A fresh green salad or roasted beetroot salad balances the rich flavours.
• With Cheese and Charcuterie: Try it with soft brie, a drizzle of honey, and cracked black pepper.
• As a Sandwich: Slice horizontally and fill with roast beef, mustard, and pickles.
• As a Snack: Reheat slices of this delicious focaccia in the oven and dip into olive oil and balsamic vinegar - divine.

It's the kind of bake that works just as well at a dinner party as it does for a quiet weekend lunch. For an ultimate onion feast, try it with our French Onion Chicken Breasts!

Storage

• At Room Temperature: Keep cooled focaccia in an airtight container or wrapped in a brown paper bag at room temperature for up to 2 days.
• Freezing: Freeze in a ziplock bag for up to 1 month. Defrost at room temperature and refresh in a preheated oven for 5-7 minutes.
• Reheating: Place slices on a baking sheet and reheat at 180°C for 5-8 minutes. The crust will crisp up beautifully.

More Sourdough Focaccia Recipes

If you love this French Onion Sourdough Focaccia that tastes just like French Onion Soup, you'll enjoy experimenting with other flavourful sourdough focaccia recipes - from classic Cherry Tomato and Rosemary Sourdough Focaccia to sweet inclusions like our Cinnamon Sourdough Focaccia and Cherry Almond Sourdough Focaccia.

Fancy travelling to Greece with your bread? Try our Feta and Lemon Sourdough Focaccia next!

Once you master the base dough, the variations are endless. Here are some different recipe ideas for you to try:

French Onion Sourdough Focaccia

Few things smell more comforting than the cosy flavour of French onion soup - slow-cooked onions, melty cheese, and a whisper of thyme - now imagine that wrapped in the soft, pillowy crumb of an airy sourdough focaccia bread recipe. French Onion Sourdough Focaccia combines everything we love about long-fermented doughs and savoury bakes: deep caramelised sweetness, crisp golden edges, and that unmistakable sourdough depth. It's the kind of bake that instantly transports your kitchen to its happiest, warmest place.

5 from 10 votes

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Prep Time 3 hours hrs 30 minutes mins

Cook Time 50 minutes mins

18 hours hrs

Total Time 22 hours hrs 20 minutes mins

Course Bread

Cuisine French, Fusion, Italian, Sourdough

Servings 8 -9 portions

Calories 266 kcal

Equipment

• Stand Mixer Fitted with A Dough Hook Attachment
• Baking Tray (9x9in/ 23x23cm)
• Parchment Paper

Ingredients

  

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Sourdough Focaccia

• 260 g strong bread flour with at least 12% protein content
• 190 ml water
• 110 g active sourdough starter 100% hydration
• 5 g salt
• 25 ml olive oil

Caramelised Onions

• 40 g unsalted butter
• 4 small brown/ yellow onions (300g - 11oz) thinly sliced
• ¼ teaspoon salt
• ⅛ teaspoon black pepper
• 1 tablespoon balsamic vinegar

Extra Toppings

• 75 g Gruyere or Comte cheese cubed
• 2-3 sprigs rosemary or thyme leaves stripped, stalks discarded

Instructions

 

DAY 1

• First thing in the morning, feed your sourdough starter and leave it in a warm spot to at least double in volume. We typically feed our starter in a ratio of 1 part starter: 1 part water: 1 part flour, and it doubles (or even triples) within 4 hours.

Fermentolyse and Mixing The Dough

• In the bowl of a stand mixer, combine flour, water and active sourdough starter. Mix the dough in a stand mixer fitted with a dough hook attachment for a few minutes on low speed, until the flour is hydrated. Cover the bowl with a damp tea towel and leave the dough to fermentolyse (a type of sourdough autolyse where sourdough starter is added too) for an hour.
• After an hour, scatter the salt on top of the dough. Drizzle the olive oil all over, and using your hands, squish the salt and oil into the dough, aiming to distribute it evenly.
• TIP: Don't be tempted to just mix the oil in by running the stand mixer - the dough will split, separated by oil layers.
• Once incorporated, run your mixer on medium speed for 10-12 minutes, until you have a very smooth and elastic dough. It will be wet, but should start gathering around the dough hook attachment.

Coil Folds, Bulk Fermentation, Cold Proof

• Scoop the dough into a lightly oiled bowl (we like to use a heavy shallow dish - it helps with coil folds later). Cover the dough with a damp tea towel or cling film (plastic wrap) and leave it in a warm spot for 30 minutes.
• Over the next 3 hours, at 30-minute intervals, perform a set of coil folds, using wet hands.
• After all 6 sets of coil folds are completed, cover the dough and let it finish its bulk fermentation undisturbed for 1.5-3 hours, depending on the temperature of your kitchen.
• Place the dough in the refrigerator for 8-24 hours (or simply overnight).

DAY 2

• The next day, line a baking tray (approx 24x24cm) with parchment paper.

Second Rise

• Take the dough out of the fridge and very carefully transfer it into the prepared baking tray, trying not to deflate it too much. Stretch it out into the corners of the baking dish.
• Cover it again and leave it in a warm spot to proof for another 1-2 hours. It will increase in volume, puff up and have very noticeable blisters across the surface.

Make Caramelised Onions

• Heat butter in a non-stick frying pan. Add the thinly sliced onions, salt and pepper.
• Stir the onions over medium heat for 5 minutes, until just starting to soften.
• Turn the heat down to low and continue cooking the onions for another 25-30 minutes until very soft and browned.
• Finally, stir in the balsamic vinegar, take the pan off the heat and set aside to cool down.

Topping and Baking

• Preheat the oven to 200°C (400°F).
• Spread caramelised onions, cubed cheese and herbs across the surface of the dough.
• Oil your fingers and dimple the toppings into the dough, pressing deep down to the base of the pan.
• Bake the focaccia for 20-25 minutes. Cool it for at least 20 minutes before slicing. Best enjoyed slightly warm or at room temperature on the day it is baked.

Video

Nutrition

Calories: 266kcalCarbohydrates: 32gProtein: 9gFat: 12gSaturated Fat: 5gPolyunsaturated Fat: 1gMonounsaturated Fat: 4gTrans Fat: 0.2gCholesterol: 25mgSodium: 409mgPotassium: 127mgFiber: 2gSugar: 3gVitamin A: 245IUVitamin C: 4mgCalcium: 147mgIron: 0.5mg

Keyword French Onion Sourdough Focaccia, Onion Sourdough Focaccia, Sourdough Focaccia With Caramelized Onions

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