Preheat oven at 210°C. Lightly grease an oven tray with vegetable oil and add red bell peppers, onions and garlic to it. Roast vegetables for 25-30 minutes.

Leave the ingredients to cool for 10 minutes and then add them to a blender. Blitz until smooth.

Meanwhile, add 300 g of spaghetti to boiling water and add a pinch of salt. Leave to cook for 8-10 minutes (don't cook the spaghetti for too long because you will add it to the sauce later). Reserve 2 cups of the pasta water for later and drain the rest away.

Heat a splash of oil in a saucepan and pour in the red pepper sauce. Then, add 2-5 tablespoon of tomato puree. Season sauce with salt to taste, pepper to taste, add 2-3 tablespoon of lemon juice, 1-2 tablespoon of vinegar, stir and bring to a boil. Leave to cook on a low/medium heat for 5-7 minutes.

Add the pre-cooked spaghetti to the sauce (add ½-2 cups of pasta water if necessary) and stir. Leave to cook for 5-7 minutes and stir in between.