Clean the rhubarb, cut into thin strips and mix with the powdered sugar.
Line a 12 cup muffin tin with paper liners. Preheat the oven to 170 ° C fan oven.
Mix the flour, baking powder and almond together. Mix egg liqueur, buttermilk, oil, sour cream, sugar and eggs with a hand mixer on a low setting until you have a bound mass. Briefly stir in the flour mixture in portions on a low level and finally fold in the rhubarb loosely.
Distribute evenly in the molds and bake on the middle rack for 25-30 minutes. Possibly do a chopstick test.