Chocolate peanut butter slab cake

Easy to share, this sweet and sticky slab cake makes the perfect tea-time treat and will be an absolute hit with peanut butter lovers.

By BTYB White Wings
  • 30 mins preparation
  • 1 hr cooking
  • Serves 12
  • Print


  • 50 g cocoa powder
  • 125 ml boiling water
  • 200 g butter, softened
  • 330 g caster sugar
  • 1 tsp vanilla extract
  • 3 eggs, lightly beaten
  • 140 g smooth peanut butter, at room temperature
  • 225 g White Wings self-raising flour
  • 35 g White Wings plain flour
  • 180 ml buttermilk
  • 220 g peanut butter-filled milk chocolate, chopped coarsely
Peanut butter ganache
  • 500 g white chocolate
  • 95 g smooth peanut butter, at room temperature
  • 250 ml pouring cream


  • 1
    Preheat oven to 180°C/160°C fan. Grease a deep 20cm x 30cm rectangular (at least 4cm deep) cake pan; line base and sides with baking paper, extending 2cm on all sides.
  • 2
    Stir cocoa and the water in a small heatproof jug until cocoa dissolves.
  • 3
    Beat butter, sugar and extract in a small bowl with an electric mixer until pale and fluffy. Gradually beat in eggs, then cocoa mixture and peanut butter until combined (mixture may look curdled at this stage). On low speed, fold in White Wings flours and buttermilk, in two batches, until smooth. Spread the mixture into the pan, level the top.
  • 4
    Bake cake for 1 hour or until a skewer inserted into the centre comes out clean. Stand cake in pan for 5 minutes before turning out onto a wire rack to cool.
  • 5
    Make peanut butter ganache.
  • 6
    Spread ganache on top of cooled cake. Decorate with peanut-butter-filled chocolate.
Peanut butter ganache
  • 7
    Place chocolate and peanut butter in a medium heatproof bowl. Heat cream in a small saucepan until almost boiling; pour over chocolate mixture, whisking until smooth. Cover; refrigerate for 1 hour, stirring occasionally until mixture is chilled and thickened. Beat thickened peanut butter ganache with an electric mixer for about 10 seconds until pale and fluffy.


The uniced cake can be made up to 2 days ahead; store in an airtight container at room temperature. The peanut butter ganache is best made on the day of serving.
Brought to you by White Wings
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