Preheat the oven to 176°C and line a the largest sheet pan you have with baking parchment. Oil it very very lightly.
Stir the dry ingredients together in a bowl. Pour in the egg whites and mix to combine.
Mix in the vanilla extract.
Drop circles of batter with a tablespoon/teaspoon, leaving at least 2 inches between them. Top each cookie with a whole almond and bake for 15 mins till the thins have a firm, glossy surface and the edges are firm and set.
Allow them to rest on the tray for 5 mins before transferring them on to a wire rack to cool completely. Store in an airtight container at room temperature.