Here are the ingredients we used. Notice there are no BPA-lined cans involved:
	•	4 pounds tomatoes
	•	1 large onion, chopped
	•	1 cup your choice of vinegar — Mark uses white vinegar. Whatever kind you buy, try to get vinegar in a glass bottle instead of plastic.
	•	1 tsp. salt
	•	1 tsp. ground cloves
	•	1 tsp. ground allspice
Drop tomatoes into a pot of boiling water for about a minute until their skins split.
Once skins have split, the peel will basically fall off. Peel and chop tomatoes.

Combine chopped tomatoes with chopped onions in a large saucepan. Make sure to catch all the juice. Simmer for about 10 minutes.
Next, transfer tomato/onion mixture in small batches to a blender with a glass pitcher (I don’t recommend putting hot foods into a plastic blender pitcher!) filling it only about half full each time. Puree each batch and pour into a bowl.

When finished pureeing, pour the entire batch back into the saucepan, making sure there are no more big chunks. Add vinegar, salt, cloves, and allspice, and stir.

Let the ketchup simmer slowly, uncovered, for several hours, stirring occasionally, until it is reduced about 50% or to the desired thickness. This ketchup ends up a brownish red color, not the artificially-enhanced red of many commercial ketchups. But believe me, it tastes fantastic.