Jammy Heirloom Tomato–Onion Relish
Judah Newman·1 hr 20 min·Makes about 2 cupsA 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.
- No-Sugar
- Thermomix
- Condiment
- Tomatoes
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
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).
Cook in the Thermomix
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 & store
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.