Just something I've thrown together, and its always requested again and again. For novice chefs, its nice to have it all spelled out for you. I like to use turkey sausage. But any will do, as well as veggie round or ground beef.
Take sausages out of their casings and brown in a large pan.
In a second large pan, over medium heat, add oil, garlic, white onions. Stir as the onions cook. Once onions have started to cook, add all other vegetables and spices, cook until soft, stirring occasionally.
Drain sausages and pat dry with paper towel.
Pour tomato sauce into vegetable pan and continue to heat. (Use a lid to avoid a mess!)
Cook pasta in boiling water until desired consistency. Drain.
In a 9x9 serving dish, layer bottom with half the pasta. Cover with sausage and 1/2 cheese. Add half the sauce/vegetable mix.
Layer a second layer of pasta, sauce and top with the remaining cheese.
Place in warmed oven and bake until the cheese melts and the dish is heated completely through. (Components can be made ahead of time, stored or frozen and piled into the baking dish before heating.).