Preheat oven to 350° F. In a pot, combine the flour and 2 teaspoons of butter. Cook for about 2 minutes. Add the whole milk and whisk until thick. Turn off the heat and add the cheddar and gruyere cheese stirring until melted. Add the uncooked cheese tortellini to the sauce. Transfer the mixture to a ramekin. Melt the remaining 1 teaspoon of butter and add to the seasoned breadcrumbs. Sprinkle on pasta and bake for about 15 minutes or until the breadcrumbs are golden. Buon Appetito!