Step 1

In a large bowl, using a pastry blender, blend the butter into the flour creating a coarse, crumb-like consistency.

Step 2

In a separate bowl, mix the egg yolks and sour cream. Add to flour mixture. Blend and knead lightly until mixture is like pie dough. Shape into small, walnut-sized balls, cover, and refrigerate overnight (makes about 52-56 balls).

Step 3

Place egg whites in an airtight container and refrigerate.

Step 4

The next day, beat the egg whites until stiff. Add powdered sugar and beat well. Stir in nuts and refrigerate.

Step 5

To a medium bowl, add 2 tablespoons each of all-purpose flour and sugar. Take half the balls out of the refrigerator and place in flour/sugar mixture. Keep the rest chilled.

Step 6

Roll balls out on a small amount of flour/sugar mixture into a thin circle. Place a heaping teaspoon of filling on each and roll up into a crescent shape. Pinch the ends tightly. Place seam-side down on a greased cookie sheet.

Step 7

Bake at 350 degrees Fahrenheit for 12 to 15 minutes. Cool slightly and dip in a bowl of confectioners' sugar. Store the kiflies in a cool place.