Pour oil in a frying pan and heat over medium-high heat. Sauté bell pepper, shallots, jalapeno pepper, and garlic 2 minutes. Place lid on pan, lower heat, and simmer 10 minutes. Pour in broth and simmer 15 minutes or until almost all the liquid is absorbed.
Using a food processor or blender, puree mixture until smooth. Strain mixture through a chinois, throwing away any solids. Mix in vinegar and salt.