Heat the oven to Gas 2, 150°C, fan 130°C. Line two baking sheets with nonstick baking paper. Whisk the egg whites until stiff using an electric whisk. Add the almonds, icing sugar, flour, vanilla seeds and quickly whisk again until smooth.
Spoon into a piping bag and pipe even-sized macaroons approximately 2.5cm (1in) across, or teaspoon onto the tray and give them room to spread.
Place in the oven and bake for 12-15 minutes, remove and leave to cool for a few minutes before transferring to a cooling wire. Store in an airtight container.
For chocolate macaroons replace 1 teaspoon of flour with sifted cocoa powder. For pink add a few drops of pink or red food colouring.