Carrot Zucchini Fritters

Name: Carrot Zucchini Fritters
Ingredients: 2/3 cup plus 1/2 cup sour cream, divided; 2/3 cup lightly packed fresh basil leaves; 1 teaspoon lemon juice; Salt and pepper to taste; 1/2 cup mayonnaise; 1/2 cup horseradish sauce; FRITTERS:; 2 tablespoons finely chopped onion; 1 tablespoon butter; 1 egg, lightly beaten; 2 medium zucchini, shredded and squeezed dry (about 1-1/2 cups); 1 large carrot, shredded; 1/3 cup all-purpose flour; 1/3 cup grated Parmesan cheese; 1 tablespoon cornmeal; 1/2 teaspoon salt; 1/8 teaspoon pepper; Oil for frying