For the oatmeal cookies, preheat the oven to 150 degrees. Beat the butter and brown sugar until creamy. Stir in the egg.
Mix the oatmeal, almonds, baking powder and lemon zest. Gradually stir into the butter-egg mixture.
Wrap the dough in plastic wrap and chill for about 30 minutes. Roll out to a thickness of approx. 5 mm, cut out circles and bake the oatmeal cookies for approx. 10 min.