Beat the margarine / butter with the sugar on the highest setting until frothy. Gradually add the eggs, milk and the baking oil. Stir everything on the highest level until creamy. Sieve the flour with the baking powder and stir into the dough in portions. The dough should keep its creamy consistency.
Preheat the oven to circulating air 170 ° (upper and lower heat 175 °). Drain the mandarins well. Fill a 12-cup muffin tin with paper liners.
Divide the batter over the 12 molds and place about 3 pieces of mandarin orange on top of each muffin. Bake the muffins on the middle rack for 20-30 minutes. Then leave to cool on a wire rack and sprinkle with powdered sugar just before serving.