Cream butter, vanilla extract, and sugar.
Add eggs and beat thoroughly.
Stir in sour cream.
Mix flour, baking soda, and salt.
Add to butter mixture and mix until a dough is formed.
Divide dough into 3 portions.
Shape each portion into a roll 1 1/2 inches in diameter.
Place each roll on a cookie sheet.
Bake at 350Â°F 15 minutes.
Remove from oven and turn oven control to 425Â°F.
Using a very sharp knife, cut into 3/4 inch slices.
Arrange slices cut side down on cookie sheets.
Bake slices first on one side, then the other, until golden brown and firm (about 6 minutes for each side).
Cool on wire racks.