3 pasta shells ricotta simple Recipes

jumbo pasta shells, cooked and drained, light ricotta cheese (use full amount if not using meat or for extra cheesey), cooked sausage, crumbled (optional), part-skim mozzarella cheese, shredded, divided, fresh parsley leaves, packed, very finely chopped, fresh romano cheese or 1/4 cup parmesan cheese, grated, egg, minced garlic (optional) or 2 tsp garlic powder (optional), nutmeg, grated, black pepper , to taste, marinara sauce or 1 (26 oz) jar homemade pasta sauce

pasta shells, fresh ricotta, egg yolks, kosher salt, black pepper, divided, parmesan cheese, grated, fresh sage or 2 tsp rosemary, finely chopped, olive oil, marinara sauce, unsalted butter