Pre-heat oven to 350°F.
Season spareribs with salt & pepper or your favourite rub.
Bake spare ribs in roasting pan until cooked (1-2 hours) until desired doneness. You can also bake for 1 hour and then broil in oven or grill on BBQ for 20-30 minutes.
In a large pot (Dutch oven) fry onions in oil until soft.
Add tomatoes, paste, oregano, Italian seasoning, and garlic powder. Bring to boil then cover and simmer on low for 20-30 minutes.
Boil rigatoni as per package instructions, drain, and mix well with sauce.
Place in oven to warm and serve with spareribs.