Jammy Heirloom Tomato–Onion Relish
A deeply savory, glossy tomato-onion relish that eats like a jam—without any added sugar or tomato paste. Fresh heirloom tomatoes cook down into a rich, spoonable spread with mellow onion sweetness and a gentle tang. Made to shine in the Thermomix: soften onions first, then reduce hard until thick and shiny, finishing with a quick blend if you want it smoother. Great with eggs, grilled cheese, roasted vegetables, or spooned alongside fish.
Total time: 80 minutes
Yield: Makes about 2 cups
Ingredients
- 2 tablespoons olive oil
- 2 medium yellow onions, peeled and cut into chunks
- 2 cloves garlic, peeled (optional)
- 1/2 teaspoon kosher salt, plus more to taste
- 1/4 teaspoon black pepper
- 3 pounds fresh heirloom tomatoes (about 6–8 medium), cored and cut into wedges
- 2 tablespoons balsamic vinegar (or 1 1/2 tablespoons red wine vinegar for a brighter tang)
- 1 teaspoon smoked paprika (optional, for smoky depth)
- 1/4 teaspoon chili flakes (optional)
Instructions
- Prep the tomatoes. Core and wedge the heirloom tomatoes. If they’re extremely juicy, you can let them sit in a bowl for 5 minutes and pour off a little of the watery juice (keep the thicker tomato pulp).
- Chop the onions (and garlic). Add onions (and garlic, if using) to the Thermomix bowl. Chop 5 sec / Speed 5. Scrape down.
- Soften and sweeten the onions. Add olive oil, salt, and pepper. Cook 10 min / 120°C / Speed 1 (MC off; use the simmer basket on top as a splash guard). The onions should look translucent and smell sweet, not sharp.
- Add tomatoes and start the reduction. Add the tomatoes. Cook 20 min / Varoma / Speed 1 (MC off; basket on top). You’re looking for lots of steam and the mixture to go from watery to saucy.
- Season and reduce to “jammy.” Add vinegar (plus smoked paprika and chili flakes if using). Continue cooking 20–35 min / Varoma / Speed 1 (MC off; basket on top), until thick and glossy. Doneness cue: when you drag a spoon through, the path should stay open for a second or two and the relish should mound on the spoon instead of dripping.
- Adjust texture. For a smoother, more spreadable relish, blend 5–15 sec / Speed 4–6, stopping when it’s as smooth as you like. For a chunkier relish, skip blending.
- Final seasoning. Taste and adjust salt and vinegar. If it tastes flat, add a tiny splash more vinegar; if it tastes too sharp, cook 3–5 min / Varoma / Speed 1 to mellow it.
- Cool. Transfer to a wide bowl to cool faster; it will thicken more as it cools.
- Store. Refrigerate in a clean jar/container for up to 5 days.
Notes
Tomato paste isn’t needed here—heirlooms bring plenty of flavor; the key is **steam-off reduction** (MC off + basket on top) until glossy and thick. If your heirlooms are very pale/mild, add 1 extra tablespoon balsamic vinegar for depth, or 1 teaspoon smoked paprika. Serving ideas: grilled cheese, burgers/sandwiches, eggs, roasted potatoes, or spooned next to salmon. Freezing: works well—freeze in small portions; thaw overnight in the fridge and stir.