Homemade ketchup is simple and much more flavorful than anything you can buy at the store. I use 4 tablespoons of sugar, but adjust the sugar to your taste.
1 tablespoon olive oil
1 medium onion, sliced into half moons
2 garlic cloves, chopped, about 1 tablespoon
1-inch piece of ginger, peeled and chopped
1/4 teaspoon to 1/2 teaspoon crushed red pepper flakes, optional for spicy ketchup
1/4 teaspoon ground allspice
2 tablespoons tomato paste
1 (28-ounce) can whole tomatoes in juice
2 to 5 tablespoons brown sugar, depending on how sweet you like your ketchup
1/4 cup apple cider vinegar
Salt and fresh ground black pepper
1Cook the onions, garlic, and ginger: Heat oil over medium heat. Add the onions and cook until they are softened, sweet, and lightly browned, about 8 minutes. Add the garlic, ginger, red pepper flakes, and allspice and cook, stirring frequently, for 2 minutes.
2Add the tomato paste: Add the tomato paste and cook, stirring it around the pan, until it turns from red to burnt orange, about 2 minutes.
3Add the tomatoes: Add the can of tomatoes with juice, 2 tablespoons brown sugar, the cider vinegar, a generous pinch of salt, and a few grinds of black pepper. Stir, and then taste to see if you need to add more sugar (we usually add a total of 3 to 4 tablespoons).
4Simmer until shiny: Bring to a simmer, reduce the heat slightly, and cook at a low simmer, stirring occasionally, until the ketchup is thickened and glossy, about 20 minutes. Taste, then adjust with more sugar, salt, or pepper as needed.
5Blend the ketchup: Use an immersion blender directly in the pan to blend everything until smooth. If using a stand blender, carefully transfer the hot ketchup to the blender. Be sure to fill the blender only halfway when blending hot liquids. Remove the small center cap from the blender lid and cover the opening with a folded kitchen towel to allow steam to escape and prevent pressure buildup. Blend until smooth.
6Store: Let the ketchup cool to room temperature before refrigerating for up to one month.