Making jams and preserves is one of the best ways of making your fruit last as long as possible – it was traditionally a way of eating fresh produce during the ‘hungry’ winter months. "I’m a big fan of adding herbs and spices to jams," says Kylee Newton of Broadway Market stall Newton & Pott and author of The Modern Preserver. "By combining different flavours, you’re creating something more versatile that can be used in unexpected ways, like in a bakewell tart or folding through ice cream." You can also make this recipe with lemon basil or lemon verbena instead of the thyme.

Ingredients

  • 650g rhubarb (fresh or frozen)
  • 150ml water
  • 650g blueberries (fresh or frozen)
  • 50ml lemon juice (about 1 lemon)
  • 750g granulated sugar
  • 2 tsp fresh lemon thyme leaves
  • A pinch of sea salt

Method

The wrinkle test

Put a teaspoon of hot jam onto a chilled plate and spread it around slightly.

Push your finger through the jam on the plate - you're looking for it to wrinkle and not flood back in to fill the gap.

If it's not ready, turn the pan back on, simmer for five minutes and test again.

Turn the heat off while you test - you don't want to overcook the jam. 

  1. If you’re using fresh rhubarb, cut it into 1.5cm pieces; if it’s frozen, defrost it first and add 50ml less water.
  2. Soften the prepared rhubarb in a large jam pan with the water on a moderate heat for about ten minutes. Add the berries, lemon juice and sugar then slowly bring to the boil, stirring to dissolve the sugar.
  3. Continue to boil on a moderate heat for 20 minutes, stirring intermittently, until the liquid has reduced and the mixture has thickened to a jammy consistency.
  4. Use the wrinkle test to check for a soft setting point then, when ready, remove from the heat. Skim off any scum from the surface, stir through the lemon thyme and salt then leave to sit for 5 minutes to infuse.
  5. Ladle into warm, dry, sterilised jars and seal. Keeps unopened for up to six months. Once opened, refrigerate and eat within four weeks.

The Modern Preserver by Kylee Newton (Square Peg, 2014)