Spicy Tomato Ketchup

• 2 large onions, cut in 1/2-inch-thick round slices
• 1 1/2 tablespoons olive oil
• 1 teaspoon coriander seeds
• 1 teaspoon cumin seeds
• 1 teaspoon mustard seeds
• 1 cup red-wine vinegar
• 1 1/4 cups packed brown sugar
• 2 tablespoons maple syrup
• 2 tablespoons honey
• 1 head garlic, cloves separated and peeled
• 1/4 cup capers with their brine
• 1/4 cup Frank's or Durkee's hot sauce
• 3/4 teaspoon paprika
• 3/4 teaspoon ground cinnamon
• 3/4 teaspoon ground allspice
• 3/4 teaspoon ground ginger
• 3/4 teaspoon dried oregano
• 3/4 teaspoon freshly ground black pepper
• 3/4 teaspoon ground cardamom
• Kosher salt, to taste
• 3 28-ounce cans whole peeled tomatoes
• 2 12-ounce cans tomato paste

1. Heat broiler.
2. In a large bowl, toss onions with olive oil to coat.
3. Place onions on a baking sheet and broil until blackened, about 10 to 12 minutes to a side.
4. In a small iron skillet over medium heat, toast coriander, cumin and mustard seeds until fragrant, about 2 to 3 minutes.
5. Grind toasted spices in a mortar and pestle or spice grinder.
6. In a deep, heavy, nonreactive pot, combine onions, ground coriander, cumin and mustard and remaining ingredients.
7. Simmer over medium-low heat about 3 hours, stirring every 15 minutes to break up tomatoes and to keep ketchup from sticking.
8. Ketchup should reduce by a third.
9. Let cool slightly.
10. In a food processor or blender, puree ketchup in batches.
11. Transfer to jars.
12. Let cool completely, then refrigerate.
13. Ketchup will keep for as long as 3 months in refrigerator, or frozen for as long as 6 months.

onions, olive oil, coriander seeds, cumin seeds, mustard seeds, redwine vinegar, brown sugar, maple syrup, honey, garlic, capers, hot sauce, paprika, ground cinnamon, ground allspice, ground ginger, oregano, freshly ground black pepper, ground cardamom, kosher salt, tomatoes, tomato paste

Taken from cooking.nytimes.com/recipes/8571 (may not work)