Combine a chopped garlic clove, a chopped onion and a carrot chopped into pea-size bits into a bowl. Add 10 1/2 ounces of lean beef mince, and pull the meat apart with a fork to stir and combine the mixture. Cover the bowl with a microwave-safe lid or plastic wrap.
Leaving a small section open, microwave the bowl on full power for three minutes. Take the bowl out, break up the mince one more time, and heat for three more minutes. Add a 14-ounce can of chopped tomatoes with 2 ounces of boiling water, and add a teaspoon of dried oregano and black pepper to taste. Crumble a beef stock cube over the whole mixture.
Mix the bowl with a wooden spoon, cover one more time, and microwave on full for seven minutes. Take the bowl out, stir it well, and put it back in for 10 more minutes. Let this bowl stand while you cook the spaghetti. Boil water for the spaghetti, and break the pasta into thirds, putting the pieces in another microwave-safe bowl.
Add a tablespoon of vegetable oil, and pour in the boiling water. Stir well, and microwave for four minutes. Take the bowl out, and stir the noodles. Cover again, and microwave for four more minutes. Allow it to stand for two minutes, and check to ensure it has cooked. Cook for more time as needed, and then drain to serve with the sauce.