Had a sudden influx of Red Onions last weekend, decided the best thing to do was dice them all up and reduce them to a mere jar of mass.

Recipe - Fills one 350g Jar

3 Red Onions, diced
1 Large Garlic Clove, minced
100g Dark Muscovado Sugar
75ml Balsamic Vinegar
25ml Cold Water
1tsp Dijon Mustard
2tbsp Oil (used Rapeseed)

1. Heat the Oil in a large, thick-bottomed saucepan on medium-low (emphasis on low) heat and gently fry the Onions for 20-30 minutes, stirring regularly so that they don't crisp up or pick up any colour.

2. When the Onions have reduced by half and most of their moisture is evaporated, add one tablespoon of the Muscovado Sugar, increase the heat to medium and fry for another 10 minutes, stirring more often so the Onions pick up more colour but don't burn or crisp up too much.

3. While the Onions fry, whisk together the Balsamic, Water and remaining Muscovado Sugar in a bowl or jug. In the last two minutes of frying, add to the pan the minced Garlic, Dijon Mustard and a heavy pinch of Salt and Pepper.

4. Add the liquid to the pan and bring to a low simmer. Let it cook uncovered for 30-40 minutes, or as long as it takes for the mixture to reduce and thicken up. For me this took almost an hour, but I put it on a very low simmer, so it's pretty subjective. Stir every now and again to make sure nothing is sticking to the bottom of the pan or burning.

5. To test if the Chutney is ready, run a spoon along the bottom of the pan. It should take a couple of seconds for the liquid to recover the bottom of the pan again. Transfer to a sterile, glass jar once it's ready and allow the Chutney to cool (either in the pan or uncovered in the jar) for up to ten minutes before sealing.

Extra Notes
- Some feedback says the Chutney was very sweet. I'd probably reduce the amount of Muscovado to 75g to compensate, but I wouldn't know without testing.
- The recipe I used as reference uses Red Wine Vinegar, not Balsamic. Your call.