Bring the butter to room temperature, add the brown sugar, and cream until white.
Add the egg and liqueur and mix well.
Sift the flour and baking powder into the dough, then fold into the batter with a spatula, scraping up from the bottom. Tip: Don't knead it.
Fold in the oatmeal and raisins.
Arrange rounded spoonfuls on a baking pan lined with kitchen parchment paper. Press lightly to make them about 7 mm thick. They're simple and cute.
Bake at 170 for 15 minutes. Once cooled, they will be dry and crispy.
This is oatmeal.