Heat oven to 160C/140C fan/gas 3. Line 2 baking sheets with baking parchment and brush with butter. Mix the butter, egg whites, sugar and flour until smooth, then add the almonds. With wet fingers or the back of a spoon, flatten tbsps of mixture into 16 biscuits on the sheets. Bake for 15-18 mins until golden. Cool. Will keep in an airtight container for 2-3 days – put pieces of parchment between to stop sticking.