We get butter or margarine in advance. In extreme cases, you can reheat it for 10 seconds in the microwave. For convenience, we take a kitchen processor, put butter, sugar, vanilla in it, mix with knives for about 1 minute.
Put the egg, mix.
Add flour and baking powder. I recommend not putting all the flour at once, it may need more or less.
Mix the mass with knives into a plastic dough.
Put the dough in a bag and put it in the refrigerator for 30 minutes.
We clean tangerines.
We take out the dough, roll it into a layer 5 mm thick, cut out the circles. I used a regular glass. The diameter of the circle should be larger than the tangerine. On a circle of dough, put a slice of tangerine on the edge.
We pinch the dough like a dumpling, with a fork we make notches along the edge.
Put the cookies on a baking sheet covered with parchment, put them in a 180-degree oven, and bake for 15 minutes.