Cream butter and both kinds of sugar with the whisk of the hand mixer. Stir in egg and vanilla extract. Mix flour and salt and stir in. Finally stir in cranberries and oat flakes.
Using 2 spoons, spread approx. 18 flat blobs (5-6 cm Ø) from the dough onto 2 baking trays lined with baking paper. Bake them one by one in a preheated oven (electric cooker: 200 °C/ circulating air: 175 °C/ gas: see
manufacturer) bake for about 10 minutes. Remove and let cool on a cake rack. The biscuits are still relatively soft when you take them out of the oven.