Pour flour (3 cups) into a bowl, add baking powder (1 teaspoon), add 180 gr. cold butter. Chop the flour and butter into fine crumbs with a knife.
Add sour cream (1 cup). Knead the dough. If, in your opinion, the dough turns out to be runny, you can add a little flour. The dough should be convenient to work with and easy to roll out into a layer. but! do not add too much flour. Next, wrap the dough in plastic wrap and refrigerate for 30-40 minutes.
Chop the walnuts washed and dried in the oven into fine crumbs.
Rinse the raisins, pour warm water for 1 hour - 1.30 minutes, then dry with a paper towel. Combine the chopped walnuts and raisins.
Remove the dough from the refrigerator, divide into two parts, roll out each part to a thickness of about 2-3 mm. With a knife or a knife - roller , cut the cake into squares of 7 - 8 cm . Put the filling of raisins and nuts in the middle of each square. Form triangles.
Place the triangles on a baking sheet covered with baking paper and send them to a preheated 180-190C oven for baking. Bake the triangles until golden brown.
Sprinkle the finished cooled triangles with powdered sugar.