Peel the onion and cut into thin strips. Heat a little olive oil in a large pan and fry the onion strips in it until transparent. Add tomato pieces to the jar, season with salt, pepper and sugar. Simmer the sauce over low heat until it is reduced by half.
Wash and halve the cherry tomatoes. Peel the garlic and cut into thin slices. Wash the chili, halve it lengthwise, remove the seeds and chop finely. Wash the parsley, dry it, strip the leaves and chop it. Finely grate the parmesan.
Cook spaghetti in salted boiling water according to package directions.
Meanwhile, wash and dry the shrimp. Heat the olive oil in a large pan. Fry the shrimp for 2-3 minutes. Salt lightly and remove. Fry the garlic slices, chili strips and halved cherry tomatoes in a pan for about 3 minutes. Season with salt and pepper.
Add spaghetti to the dripping tomato sauce, toss and sprinkle with parmesan.
Fold the parsley and shrimp into the cherry tomatoes. Reheat everything. Season with salt and pepper.
Spread the spaghetti on preheated plates. Garnish with the shrimp and cherry tomato mixture and drizzle with a little olive oil.