Though purportedly named after the Italian opera singer Luisa Tetrazzini, this baked noodle dish is American, not Italian, and recipes for it only date back to the early 20th century. I think tetrazzini is something that everyone adapts into their own thing. Some people add ketchup. Others use canned mushrooms and omit the red bell pepper. But this version, with a smattering of colorful vegetables and a sauce enriched by sherry and parmesan, is my favorite.