I made this homemade ketchup awhile back. It is super easy and has a depth of flavor that is just AMAZING. (I am semi-ashamed to admit that I ate a few warm spoonfuls straight from the pan!) And best of all, it keeps in the fridge for up to 3 weeks, so you can enjoy it again and again.
Note: The full 2/3 cup of brown sugar may make the ketchup a little too sweet if you prefer a tangier ketchup. Try adding 1/2 cup in the beginning, then taste and add more if necessary about 30-45 minutes into cooking if you are concerned.
From Gourmet.com (Oh, how I miss Gourmet magazine!!! *Tear*)
INGREDIENTS
1 (28-oz) can whole tomatoes in purée
1 medium onion, chopped
2 tablespoons olive oil
1 tablespoon tomato paste
2/3 cup packed dark brown sugar
1/2 cup cider vinegar
1/2 teaspoon salt
DIRECTIONS
1. Purée tomatoes (with purée from can) in a blender until smooth.
2. Cook onion in oil in a 4-quart heavy saucepan over moderate heat, stirring, until softened, about 8 minutes. Add puréed tomatoes, tomato paste, brown sugar, vinegar, and salt and simmer, uncovered, stirring occasionally, until very thick, about 1 hour (stir more frequently toward end of cooking to prevent scorching).
3. Purée ketchup in 2 batches in blender until smooth (use caution when blending hot liquids). Chill, covered, at least 2 hours (for flavors to develop).



