Place a large, heavy-bottomed frying pan over medium heat and add the olive oil. Heat it for 2 minutes, then swirl the oil to cover the bottom of the pan.
Add the onions and sauté them until transparent, stirring frequently. Avoid browning them.
Add the long green pepper and continue to sauté for another 5 minutes. Stir constantly to avoid burning the vegetables, and reduce the heat if necessary.
Add the garlic and sauté for another minute.
Add the tomatoes and paprika, then reduce the heat to medium-low. Stir frequently and simmer for about 15 minutes, or until the mixture has a thick, sauce-like consistency.
Pour the sofrito into mason jars and store in the fridge for up to a week. Use in your favorite Spanish recipes, or enjoy on its own with fried eggs.
