You can buy ground Hazelnuts in any supermarket in France and in some speciality shops here.
Today I decided to try substituting them for almonds in my favourite biscuit recipe (favourite because it is foolproof, simple and delicious).

They taste fantastic, might even be worth skinning and grinding hazelnuts especially to make them up.

Hazelnut Macaroons
(Will give you about 36 little biscuits)

200g (7 oz.) Ground Hazelnuts (or Almonds)
200g (7 oz.) Caster Sugar
2 Egg Whites
Some Pistachios or split Almonds to garnish.

Mix the sugar and ground nuts well together.
Add in the egg whites and mix to a stiff dough.
Set the oven to Gas 4, 175C, 350F.

Line two baking sheets with non-stick paper.
(I find if you sprinkle a little water on the baking sheet it helps to get the paper to lie down flat and then it is easier to work)
With dampened hands (or 2 teaspoons) make walnut sized balls of the dough and lay these out in rows (not too close) on the sheets.

Flatten these slightly with a damp fork.
Press a Pistachio, or a half Almond into each one.
Bake these at the set temperature for about 15 mts or until nicely browned.
Take off the paper gently (they will still be soft) and leave to cool and crisp up on a wire rack.