1: Preheat the oven to 390°F (200°C). Put 1 egg and 90 g caster sugar into a large bowl and mix.
2: Add 200 g ground hazelnuts and mix again. This should give you a fairly thick paste.
3: Weigh out pieces of about 1 oz (30 g), roll into balls and arrange on a sheet of cooking parchment (or a silicon mat, as shown in the photo), laid on a baking sheet.
4: Pinch each ball between your fingers twice, at right angles, to give a pyramid shape. Dip your fingers in cold water if the mixture begins to stick.
Depending on the size of your egg, you might need to adjust the quantity of ground hazelnuts. For an elegant finishing touch, stick a whole hazelnut (without its skin) on top of each pyramid.