Bread & Butter Onions

Ingredients

• 1 kg (2¼ lb) firm onions — brown, red, or a mix

• 250 ml (1 cup) cider vinegar

• 150 ml (⅔ cup) water

• 100 g (½ cup) granulated sugar

• 2 tsp fine sea salt

• 1 tsp mustard seeds

• ½ tsp celery seeds

• ½ tsp ground turmeric

• ¼ tsp chilli flakes (optional)

• 2 bay leaves

• 2 tbsp unsalted butter (for the warm serving option)

Equipment

• Large saucepan or preserving pan

• Sharp knife and chopping board

• Measuring jug and spoons

• Sterilised glass jar (1-litre capacity) if storing

• Wooden spoon

Method

Step 1 — Prepare the onions (5 minutes, low intensity)

Peel the onions, halve them, and slice into 5 mm (¼ inch) half-moons. Keep the slices reasonably thick so they retain bite after cooking. Set aside.

Step 2 — Bloom the spices (2 minutes, low intensity)

In a dry saucepan over medium-low heat, toast the mustard seeds and celery seeds for 60–90 seconds until fragrant and just popping. Do not let them scorch.

Step 3 — Build the brine (3 minutes, low intensity)

Add the vinegar, water, sugar, salt, turmeric, chilli flakes (if using), and bay leaves to the pan. Stir over medium heat until the sugar and salt dissolve fully — about 2–3 minutes. The liquid should be hot but not yet boiling.

Step 4 — Simmer the onions (10–12 minutes, medium intensity)

Add all the onion slices to the brine. Bring to a gentle simmer over medium heat, then reduce to medium-low. Cook uncovered for 10–12 minutes, stirring occasionally, until the onions are softened but still hold their shape and the brine has reduced slightly. Do not overcook — they should be tender-crisp, not mushy.

Step 5 — Warm butter finish (2 minutes, low intensity — optional)

For a warm, buttery serving, melt the butter in a wide frying pan over low heat, then fold in the drained onions and toss for 1–2 minutes until glossy. Reserve the brine for drizzling.

Step 6 — Cool and chill (2 hours, passive)

Transfer the onions and brine to a sterilised jar. Cool to room temperature (about 30 minutes), then refrigerate for at least 2 hours for the flavours to develop. The onions keep for up to 2 weeks refrigerated.

Time & Intensity Summary

Serving Suggestions

• Warm, buttered, alongside roast chicken, sausages, or steak

• Cold from the jar with mature cheddar and sourdough

• Folded through a potato salad or grain bowl

• Layered into a grilled cheese sandwich

Nutrition (per serving, approx.)

Based on 6 servings, including the optional butter.