Preheat oven to 325°.
Beat egg whites.
Beat egg yolks and stir in ham, 1/2 cup sour cream, and pepper.
Fold whites into egg yolk mixture.
Coat an ovenproof 10-inch skillet with cooking spray and heat over medium heat.
Pour eggs in.
Reduce heat and cook 5 minutes or until light brown on bottom.
Bake in oven for 15 to 18 minutes or until knife comes out clean.
Fold omelet in half and place on a warm plate.
Slice and spread remainder of sour cream over top.