Spinach and Cheese Grits Frittatas

Name: Spinach and Cheese Grits Frittatas
Ingredients: 1/4 cup freshly grated Parmesan cheese; 8 cups water; Salt; 3 cups stone-ground yellow or white grits (see Note); Two 5-ounce bags baby spinach; 2 cups flat-leaf parsley leaves; 6 tablespoons unsalted butter, 5 tablespoons softened and 1 tablespoon melted; 2 large garlic cloves, minced; Freshly ground pepper; 3 ounces chilled tetilla cheese, coarsely shredded (1 cup); 3 ounces chilled Mahón cheese, coarsely shredded (1 cup); 1 1/2 ounces chilled young Manchego cheese, coarsely shredded (1/2 cup); 6 large eggs, lightly beaten