Protein - Add some cooked chicken, sous vide chicken breast, sautéed shrimp, seared scallops or sheet pan salmon would be delicious in this spicy vodka sauce pasta.
Cheese - switch out the parmesan for asiago, Romano or provolone for a little flavor variation.
Vegetables -when cooking the onions and garlic, add in some veggies like bell peppers, mushrooms, zucchini, peas or asparagus to get in more vegetables.