Mix oat flour, almond flour, and almond slices in a bowl.
Add egg whites, oligosaccharide syrup, and vanilla extract, then knead into a dough.
Divide the dough into equal portions and shape into round balls.
Place parchment paper on the baking tray and arrange the dough on it.
Bake in the oven at 170°C for 15 minutes.
Let cool, then serve.