Onion-Topped Sausage 'n' Mashed Potato Casserole

sweet ground turkey sausage, casings removed*

diced tomatoes in sauce

loosely packed fresh basil leaves, chopped**

shallot, chopped

salt-free garlic-and-herb seasoning

refrigerated garlic-flavored mashed potatoes

shredded Italian five-cheese blend

dried Italian seasoning

French fried onions