Slice the onions very thinly and evenly. A mandoline makes short work of this, but a very sharp knife and a steady hand will work well too. Caramelize onions, cook rigatoni.
Heat olive oil in a large oven-safe skillet over medium-high heat. Add the onions and sauté, stirring regularly, for about 3-4 minutes or until the onions are starting to become translucent and very slightly browned. Reduce the heat to the lowest setting and let the onions caramelize. Stir occasionally to avoid hot spot, but make sure to spread the onions across the pan as evenly as possible. This whole process takes about 20-30 minutes, and is completed when the onions are a deep yellow-brown and very much reduced in size. If the onions begin to scorch at all, remove them from heat (you might need to use a smaller coil on your stove) and/or add a little more oil.
While the onions are caramelizing, cook the rigatoni in a large pot of salted water and set it aside. Measure and set aside the remaining ingredients.
Remove the cooked onions from the pan and turn the heat back up to medium-high. Add the beef and cook until well-browned,; about 3-4 minutes. Drain the excess fat and water from the pan as the beef cooks.
Add the wine to the pan and let it deglaze the cooked bits from the bottom. Add the tomato sauce and spices and sauté for another 5 minutes. Return the onions to the pan and add the peas, then stir to combine.
Turn on your broiler (full broil/high/500°F/260°C). Sprinkle the food in the pan with shredded cheese and broil for 3-4 minutes or until cheese is well melted and starting to brown.
Notes
For a leaner version, replace the beef with ground turkey or chicken. For a vegetarian version, substitute French or green lentils for the beef.I make and can my own tomato sauce, and that simple but flavourful stuff is what I use when I specify 'tomato sauce.' That being said, I don't expect everyone to be in the same boat, so you can easily use a store-bought alternative. Avoid any of the 'complicated' sauces with lots of added veggies, spices, cheeses, etc. You're looking for the flavour of good tomatoes, maybe a few herbs, and nothing more. If you can't find a store-bought tomato sauce that's to your liking, simply use a jar of good quality crushed tomatoes or passata. You might have to use a few more spices (consider adding a bit of garlic too) and/or cook it down a bit longer, but it will work brilliantly.