Boil the spaghetti according to package directions in a pot with 1 gal (4 L) of water and a pinch of salt. Clean and chop the onions finely.
Put the olive oil in a pan and heat it on the stove. Add the onions and braise until golden. Cut the sausages into small pieces, you can use chorizo.
Put the sausages into the pan with the onions and braise until golden. Next, add the finely chopped garlic clove and stir.
Pour in the tomato sauce with 1 tsp sugar, season with salt and black pepper and leave the mixture to boil until the liquid evaporates and sauce thickens.
Add a little basil, strain the spaghetti and put them in the pan, stir and remove from the stove.
Serve sprinkled with grated parmesan. If you don't have any you can use cheese. Pour in a few drops of olive oil and finish off with several parsley leaves.