paprika garnish leaves sorrel
Cook sorrel in boiling salted water in large saucepan until tender, about 1 minute. Drain well. Squeeze dry, then pat dry with paper towels. Whisk eggs, 2 tablespoons sour cream, cayenne pepper, salt and pepper to blend in medium bowl. Mix in cooked sorrel.
Preheat broiler. Peel potato and finely chop. Melt butter in heavy 10-inch broiler proof skillet over low heat. Add shallot and cook until tender, stirring frequently, about 6 minutes.
Increase heat to medium. Add potato and stir until coated with butter. Add egg mixture. Reduce heat to low and cook until bottom of frittata is set and only top surface is runny, about 10 minutes.
Spread 3 tablespoons sour cream over top. Sprinkle lightly with paprika. Broil until top is light brown, watching carefully. Transfer to platter.
Surround with sorrel leaves. Cut into small slices. Serve hot or at room temperature.
Can substitute torn spinach leaves.