Chipotle Ketchup - cooking recipe

Ingredients

1 medium sweet onion, diced
1 tablespoon olive oil
28 ounces can whole tomatoes
1/2 cup apple cider vinegar
1/4 cup brown sugar
1 teaspoon molasses
1/2 teaspoon cinnamon
1/2 teaspoon ground cloves
1 teaspoon celery seed
3 chipotle peppers in adobo seasoning
salt, to taste

Preparation

On medium low heat, cook the diced onion in the olive oil in a medium-sized pot just until the onions start to brown a bit on the ends.
Add the tomatoes and their juice to the pot, crushing the tomatoes with the back of a spoon.
Stir in the rest of the ingredients, bring to a boil and then simmer for an hour, stirring occasionally.
After an hour, puree the mixture, and then continue to cook on low heat until it reaches your desired thickness.