Source: Enlitened Kosher Cooking by Nechama Cohen

Homemade ketchup made with tomato paste, vinegar, soy sauce, and onion powder.

Servings

8 oz no-salt tomato sauce
0.75 cup tomato paste
0.25 cup cold water
1 tbsp vinegar
2 tsp light soy sauce
2 tbsp sweetener (sugar substitute) , equal to 2 tbsp sugar
2 tsp onion powder
0.25 tsp ground allspice
0.12 tsp ground cloves (optional)

1 In a saucepan over medium heat, combine all the ingredients.
2 Simmer for 5 minutes, mixing with a wooden spoon.
3 Cool and store refrigerated in an airtight container for up to 1 week.