Edit: New and improved after tweaking. (June 14/05)

It is a variation on this recipe courtesy of Dyberrah. It's absolutely fantastic! It's really the closest I've gotten to Heinz so far. I am going to create a Heinz duplicate if it's the last thing I ever do. (Heinz One Carb ketchup isn't available here.)

1 small can (384 mL/12 oz) of plain, sugar-free tomato sauce
1 small can (6 oz) tomato paste
2 tsp vinegar (I used apple cider)
3/4 tsp garlic powder
1/2 tsp onion powder
a pinch of ground cloves
1/4 tsp allspice
1 packet of Splenda
6 drops stevia (or add more Splenda)

Combine all ingredients except Splenda. Simmer gently for 10-15 minutes. Allow to cool. Add Splenda. Store in the fridge.

The only down side to making this is that it only lasts a couple of weeks, whereas store-bought LC ketchup is better preserved and will last longer.