But what kind of adventure or discovery could possibly lurk in an über-traditional spaghetti and meatballs? Plenty, unless your Nonna has already taught you the secrets of slow-cooked Sunday Gravy.

Kaytee Hadley, a dietitian and adviser for Impossible Foods, recommends the brand’s Italian-style meatballs, which offer 12 grams of protein per serving. You can also whip up meat-free meatballs ...