• Note: some of these steps can/will happen simultaneously

Recipe yields 8 half-pint jars.

Making the ketchup

• Measure the de-seeded pulp into a stock pot along with chopped onion and red pepper. Bring to a boil and let cook at a low boil for 30 minutes, stirring occasionally. It will take about 30 minutes to reach a boil, depending on your burner and whether or not you're starting with refrigerated or room temperature pulp.
  14 cups tamarillo pulp, 1 cup onion, 1 cup red pepper
• Tie the cinnamon, allspice, cloves, and bay leaves into a square of cheesecloth.
  2 cinnamon sticks, 1 teaspoon whole allspice, 1/2 teaspoon whole cloves, 2 bay leaves
• Use an immersion blender to finely puree the cooked ingredients, then add the vinegar, sugar, and spices. 
  1 1/3 cups apple cider vinegar, 1 1/4 cups sugar, 4 teaspoons sea salt, 1 teaspoon black pepper, 2 teaspoons mustard
• Return to a simmer and cook for another 1-1/2 to 2 hours or until the ketchup reaches the desired consistency. Be sure to stir often to prevent scorching. You may need to stir more frequently as the sauce thickens.
• The foam that rises to the top of the ketchup as it cooks can be skimmed from the pulp to make a nicer looking product.
• Remove the cheesecloth bag.

Prepare for canning

• Wash the jars you'll use, making sure each is clean and free of nicks in the rim, which could impede sealing.
• Wash the lids and rings in hot soapy water. (If you're using non-Ball brand lids, prepare as suggested by manufacturer.)
• Place empty jars in a canning pot or large stock pot with enough water to cover by an inch or two, cover pot, and set on high heat. It can take awhile for the water to heat, so get it started before you begin making the recipe.

Canning this recipe

• Remove the empty jars from the canner, draining the water back into the pot.
• Transfer the hot ketchup to canning jars using a ladle and a canning funnel, leaving a 1/2" headspace between the top of the ketchup and the jar rim.
• Wipe the rims thoroughly with a damp cloth. Residue on the jar rim can impair sealing. 
• Set a flat lid on each jar as you fill it and screw on a canning band to fingertip tightness. 
• Use a jar lifter to transfer the jars into boiling water in the canner. Return water to a boil and process for 20 minutes.
• When time elapses, lift jars from the canner onto a clean towel on a solid surface. Place them where they won't be in a draft or be disturbed for 24 hours. Resist pressing the lids, as you don't want to accidentally push one in and create a false seal. 
• Check seals after 24 hours. The lid should be solid; if it flexes, the seal failed. Keep that jar in the fridge and use it first. 
• Wash jars and store in a cool, dry, dark place without their canning rings.