Spaghetti all'Amatriciana

Ingredients
4 onions
2 cloves garlic
400 gr tin tomatoes
small tin of tomato paste
pack of salted bacon from Delhaize or similar (e.g. pancetta)
1 tsp chili flakes
olive oil
Method
Chop onions and mince garlic, cube bacon
Put olive oil in a pan and add the meat, fry until crisp
Add the onions and garlic for a few minutes until soft
Add salt, pepper and chili flakes
Add tomatoes and stir, reduce heat and continue stirring occasionally for 15-20 minutes