How to turn spent coffee grounds into barbecue sauce – recipe | Waste not

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Hands shred oyster mushrooms on a cutting board next to a pan of dark sauce and flatbreads.
Tom Hunt’s spent espresso barbecue sauce, here served with Venezuelan corn cakes and ‘pulled’ oyster mushrooms. Photograph: Jenny Zarins/The Guardian.

Spent coffee grounds add depth to a smoky-sweet, intense barbecue sauce that’s a knockout with pulled mushrooms, grilled veg and meat alike

Three pillars underpin my cooking style – pleasure, people and planet – and I believe that all three need to be taken into account to make a truly delicious and nourishing meal, hence the title of my most recent book, Eating for Pleasure, People & Planet. Today’s recipe is taken from one of the tastiest recipes in the book, Venezuelan corn cake arepas with “pulled” oyster mushrooms and this sweet, umami-rich and intense barbecue sauce, all topped with a refreshing kohlrabi and mango salsa.

Spent espresso barbecue sauce

Here, I’ve added spent coffee grounds to the original barbecue sauce in my book, not only to save on waste, but also to add serious depth of flavour and further complexity to the sauce. As well as all the usual meaty suspects, from chicken wings to ribs, it’s delicious as a marinade for grilled vegetables, or as a simple condiment.

Makes About 500g, or 1 large jar

2 tbsp extra-virgin olive oil
2 onions, peeled and finely diced
4 garlic cloves, peeled and roughly chopped
4 tbsp spent espresso grounds
1 tbsp smoked paprika
1 tsp ground allspice
1 tsp freshly ground black pepper
4 tbsp blackstrap molasses
2 tbsp miso
40ml apple cider vinegar
100ml cooked tomatoes (homemade or from a tin)

Put the oil in a heavy-based frying pan on a medium-low heat, then slowly sweat the onions and garlic for about 15 minutes, until they caramelise and go very soft.

Stir in the spent coffee grounds and all the spices, cook for five minutes more, then stir in the molasses, miso, vinegar and tomatoes. Bring the sauce to a gentle boil, turn down to a simmer and cook for about 20 minutes, or until the sauce has thickened to your liking.

Leave to cool, then decant into a clean jar, seal and keep in the fridge for up to a week; alternatively, put it in a sealed container and freeze for up to six months.

• This article was edited on 3 June 2026. An earlier version omitted to say when the spent coffee grounds should be added to the sauce; they should go in when the onion and garlic are ready.