Step 1

Preheat the oven to 180°C/350°F/gas

Step 2

Line a 20cm x 30cm roasting tray with a sheet of greaseproof paper, then generously grease the paper with butter.In a food processor, blitz the butter and sugar together, then crack in the eggs, add the flour and blitz until smooth. Snap in the chocolate and pulse into the mixture until it’s in small chunks.Use a spatula to scrape the mixture into the lined tray, spreading it out evenly.Loosen the peanut butter with 2 tablespoons of warm water, stir the jam to loosen it, then spoon both over the mixture and use a cocktail stick to ripple them together through the surface, however you wish.Bake for 30 minutes, or until golden. Leave to cool, then slice and serve. Nice with a cup of tea.