Red onion marmalade is led by red onions, which make up 52% of the recipe, alongside 15% balsamic vinegar. Demerara sugar and soft brown sugar are combined with redcurrants, sugar, fruit pectin, water and salt, completing the recipe for a preserve that brings sweet and savoury ingredients together.

Highfield Preserves handcrafts this marmalade in small batches using traditional open pans. The red onions are slowly cooked in balsamic vinegar until richly caramelised, producing the sweet, tangy and deeply flavourful character of the finished marmalade, together with its noted acidity and crunch.

Professional chef Mark Dodson describes it as "nicely acidic with crunch and sweetness", recommending it for pâtés, terrines and meaty flavours. Beyond those pairings, it can be served with cheeses and hearty farmhouse platters, giving the marmalade a place at relaxed lunches and informal suppers, or making a considered choice for someone who keeps savoury preserves for fuller-flavoured food.