This onion and chilli marmalade is a rich, sweet, and gently spiced preserve that turns a simple set of ingredients into something truly special. With a mix of red and brown onions cooked slowly until soft and caramelised, this recipe creates a deep, mellow base that carries layers of flavour. Soft brown sugar adds warmth and richness, while a splash of port brings a round fruity note that sets this marmalade apart from more traditional versions. The cider and balsamic vinegars balance the sweetness with a bright, tangy lift, and the combination of mixed herbs and crushed chilli flakes gives the finished marmalade a subtle aromatic edge along with a pleasant touch of heat.

The long, slow cooking process is what makes this recipe shine. As the onions soften, their natural sugars intensify and blend with the brown sugar and port, creating a glossy, sticky texture with a complex taste. The chilli flakes infuse slowly, offering warmth that supports the sweetness rather than overwhelming it. The mixed herbs add gentle depth that sits in the background, making each spoonful feel full and rounded. Together, these ingredients produce a marmalade that is both comforting and bold, with flavours that continue to develop as it cools and rests.

This marmalade is incredibly versatile and keeps well, making it ideal for preparing ahead. It is perfect alongside cheese, especially anything sharp or creamy, and works beautifully with sausages, grilled meats, or roasted vegetables. You can stir it through gravies and sauces for extra richness, or use it in toasted sandwiches and burgers for a sweet, tangy lift. It is one of those jars you will find yourself returning to again and again.

Easy to prepare and packed with character, this onion and chilli marmalade brings warmth, depth, and a little sparkle to everyday cooking.

Onion and Chilli Marmalade

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Prep Time 10

Cook Time 2 15

Servings 4 jars

Ingredients

2 kg red and brown onions
6 tbsp olive oil
300 g soft brown sugar
200 ml port
4 tbsp cider vinegar
4 tbsp balsamic vinegar
2 tsp mixed herbs
2 tsp crushed chilli flakes

Instructions

Peel and slice the onions
heat the oil in a large pan, add the sliced onions and cook down for 25-30 mins on a low to medium heat, stirring occasionally
add 100g of the sugar and cook for a futher 15 mins
add the remaining ingredients and allow to continue cooking for another hour and a half
When the marmalade is about 15 minutes from finishing cooking, pre heat the oven to 160C, wash your jars in hot soapy water and place in the oven on a tray for at least 10 mins to sterilise
while the jars are still hot, spoon the onion mixture in and seal the lids on immediately
allow to cool and store in a cool dry place, once opened store in the refrigerator