Sweat the red onion

• Heat the olive oil in a large pan over medium heat.
• Add the sliced red onion and cook until soft and translucent.

Add the tomatoes and basil

• Add the plum tomatoes and cherry tomatoes to the pan.
• Season with salt and add the basil leaves.
• Cook until the tomatoes start to break down.

Add water and spaghetti

• Pour in the water, then add the spaghetti, breaking them if needed to fit the pan.
• Bring to a gentle simmer.

Cook the pasta, stirring occasionally

• Stir the pasta from time to time so it cooks evenly and does not stick.
• Add a little more water as needed, a splash at a time, never all at once.
• Cook until the pasta is almost al dente, following the package time.

Taste and finish

• Taste the pasta to check it is ready.
• Adjust with a little salt and a drizzle of olive oil.
• Serve immediately.