Sauté the onion

• Heat the olive oil in a large pan.
• Add the chopped onion and cook until soft and translucent.

Brown the meat

• Add the ground meat and break it up with a spoon.
• Season with salt, black pepper and oregano.
• Cook until the meat is browned.

Build the sauce

• Stir in the tomato paste and cook briefly.
• Add the diced tomatoes and mix well.
• Simmer until the tomatoes break down into a sauce.

Cook the pasta in the pan

• Add the spaghetti to the pan and pour in enough water to cover.
• Cook, stirring regularly, until the pasta is al dente and the liquid has reduced.

Add the cheese and serve

• Take the pan off the heat and stir in the grated cheese until melted.
• Serve hot straight from the pan.