Preheat the oven to 170C .
In a large bowl or an electric mixer with a whisk attachment, beat the eggs until firm peaks are reached. Add caster sugar one teaspoon at a time and keep of whisking until your meringue looks smooth and glossy.
Fold ground almonds gently into your meringue, until just mixed (don't worry if some white streaks are still showing).
Line a baking tray/ sheet with baking parchment. Using a large tablespoon, place 8 equal heaps of almond meringue, leaving at least 2 cm between them (they will expand). If using, place a blanched almond on top of each biscuit.
Bake in the middle shelf for about 15 minutes until they are golden brown.
Leave to cool slightly on the baking sheet (about 15 minutes), before transferring to cool completely on a cooling rack.