Beat egg whites at medium speed with an electric mixer until stiff peaks form.
Whisk egg yolks until thickened. Stir in potato and next 4 ingredients. Fold in egg whites.
Pour oil to a depth of 1/2 inch in a large heavy skillet; heat to 350°. Drop potato mixture by teaspoonfuls into hot oil; fry, in batches, 1 to 2 minutes on each side or until golden. Drain on paper towels. Serve immediately with sour cream and black caviar.
If you follow any social media, you’ve probably heard of “caviar butter”. Caviar butter is made by combining caviar and butter, giving it a unique, earthy flavor that will elevate your appetizer and give it a unique salty flavor. You can make your own caviar butter using your favorite ingredients and this easy-to-follow recipe.