Melt butter in a small saucepan over low heat. Once melted, stir in 1/2 cup sugar, sour cream and salt. Remove from heat and let cool some while you proceed with next step.
Measure warm water in a glass measuring cup. Stir in yeast and sugar. Let sit 5 minutes.
Add 4 cups flour to a mixing bowl for an electric mixer. Make a well in center and add salt, yeast mixture and eggs.
Add sour cream mixture and turn mixture on LOW. Once mixed fairly well, turn mixer to MEDIUM and mix for 1 minute.
Dough should be soft, not a tight ball, but add a little extra flour (up to 1/2 cup) if too wet. (I added 1/4 cup).
Cover bowl with plastic wrap and refrigerate overnight.
Punch dough down and shape into balls about the size of a golfball. You should get 16-20.