Melt butter in microwave.
Mix sour cream and eggs in a stand mixer. Add in melted butter and continue beating until well-blended.
Measure 1 cup of flour and add to the mixing bowl. Beat until incorporated with the wet ingredients, then add a second cup of flour.
Continue adding the remaining flour, stopping when the dough is still wet but can be worked with your hands.
Flour your working surface and turn dough out onto surface. Knead until dough becomes stretchy and smooth.
Cover the dough with plastic wrap while you make the filling.