Pre-heat the oven to 220 C, 425 F, Gas Mark 7.
Mix the vanilla sugar with the egg white, add the flour and the roughly chopped almonds and blend together to form a soft mixture. Spread this out on a lightly floured surface to form an oblong about 1 cm thick and 8 cm wide. Cut across-wise at 1–2 cm intervals to make the biscuits.
Gently lift them on to two baking sheets lined wit