1. Heat the Oil:

1. In a medium, high-sided skillet or pot, heat the olive oil over medium heat for 2 minutes.

2. Sauté Aromatics:

1. Add the finely chopped onion and minced garlic to the hot oil.
2. Sauté gently until soft, fragrant, and translucent (about 3-5 minutes). Be careful not to brown the garlic, as it can become bitter.

3. Cook Tomatoes:

1. Stir in the chopped tomatoes (fresh or canned).
2. Cook for 5-7 minutes, or until the tomatoes start to caramelize slightly and release their juices. If using fresh tomatoes, this step helps to develop their flavor.

4. Add Stock and Pasta:

1. Pour in the chicken or vegetable stock.
2. Add the uncooked spaghetti to the skillet, ensuring it’s fully submerged in the liquid. You may need to break the spaghetti in half to fit it in the pan.
3. Bring to a simmer.

5. Cook Pasta:

1. Let the pasta cook for about 15 minutes, or until it’s al dente (firm to the bite). Stir occasionally to prevent the pasta from sticking to the bottom of the pan.
2. The liquid should reduce and be mostly absorbed by the pasta. If needed add a splash more stock or water if it looks dry before the pasta is cooked.

6. Combine Ingredients:

1. Gently stir in the double cream (heavy cream) and most of the chopped fresh basil (reserve some for garnish).
2. Let the pasta sit for a couple of minutes to allow the flavors to meld and the sauce to thicken slightly.

7. Serve:

1. Serve hot, garnished with the reserved fresh basil.