Cut up your ingredients while waiting for the pasta water to boil.

Cook the capellini as directed on the package minus one minute of cooking time. Capellini usually takes 3 minutes to get to al dente, so cook for 2 minutes.

While the capellini is boiling, drizzle no more than a teaspoon of olive oil in a small pan. Add bacon and cook until slightly crisp. The pasta should be ready by now. Reserve 1/2 cup pasta water, then drain the pasta and set aside.

Add the tomatoes, onions, and garlic to the bacon. Cook until tomatoes are softened, about 1 minute. Add the tomato paste and cook for 30 seconds so it can caramelize.

Add cooked pasta and 2 to 4 tablespoons of pasta water. Add more pasta water if needed.

When the sauce has thicken to the consistency you like, add as much fresh mozzarella cheese as you like. Remove from heat and fold in the cheese.