Beat the eggs well with a sugar mixer.
Add very soft butter or even melted butter, and whisk again.
Then add half a can of condensed milk, about 190 g., Sour cream, add vanillin, flour with baking powder and mix thoroughly. Flour can take more or less, the dough should be a little thicker than sour cream.
Put the finished dough in molds and bake in a preheated oven to 170 degrees for about 25-30 minutes.
Remove the finished muffins from the oven, let cool slightly, then remove them from the tins and serve.
According to this recipe, the muffins are very tender and airy, the main thing is to calculate with flour, the dough should be a little thicker than sour cream. In such cupcakes, you can also add the filling in the form of boiled condensed milk, coconut, marmalade, chocolate and anything else you want.