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oat and marshmallow crispy bars on a board.
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5 from 2 votes

Oat and Marshmallow Crispy Bars

Crumbly oat biscuits, topped with chewy marshmallow and rice crispies and dipped in chocolate
Prep Time1 hr
Cook Time20 mins
Course: afternoon tea, Cake, Snack
Cuisine: British
Keyword: baking, biscuits, chocolate
Servings: 16 bars
Calories: 233kcal


  • 20cm (8in) shallow square baking tin
  • baking parchment


For the biscuit base

  • 150 g (5oz) butter
  • 150 g (5oz) golden caster sugar
  • 150 g (5oz) rolled oats
  • 150 g (5oz) plain flour (all purpose flour)

For the marshmallow layer

  • 200 g (7oz) marshmallows
  • 2 tablespoon milk
  • 75 g (3oz) puffed rice cereal

To complete

  • 500 g (1lb 2oz) milk chocolate
  • 50 g (2oz) plain dark chocolate (optional)


To make the biscuit base

  • Preheat the oven to 180℃ (160℃ fan)/350°F/gas mark 4. Line a shallow 20cm (8in) square cake tin with baking parchment.
  • Place 150g (5oz) butter and 150g (5oz) golden caster sugar in a medium sized saucepan and heat gently over a low heat, stirring until the butter melts and combines with the sugar.
  • Remove from the heat and stir in 150g (5oz) rolled oats and 150g (5oz) plain flour, beat until combined then tip into the lined tin and press into an even layer.
  • Bake for 20 minutes. remove from the oven and set aside.

To make the marshmallow crispy layer

  • Place 200g (7oz) marshmallows in a small heavy based pan with 2 tablespoon of milk. Heat over a low heat stirring until the marshmallow has completely melted.
  • Mix in 75g (3oz) puffed rice and stir to coat in the marshmallow. Tip on top of the biscuit base and spread level. Allow to cool completely.

To complete

  • Line one or two baking sheets with nonstick baking parchment. Carefully remove the biscuit slab from the tin and cut into 16 bars or 32 bites or a mixture of the two with a sharp knife.
  • Break 500g (1lb 2oz) milk chocolate into pieces and place about ⅔ in a bowl over a pan of gently simmering water (base of the bowl should not be touching the water). Heat gently stirring until the chocolate has melted.
  • Chop the remaining chocolate into smaller pieces. Remove the bowl of melted chocolate from the heat and stir in the remaining chopped chocolate. Stir until melted.
  • Carefully dip each biscuit bar into the melted chocolate to coat. Lift out of the bowl on a fork and allow the excess chocolate to drip back into the bowl. Wipe the base of the bar gently on the side of the bowl and transfer to the lined baking sheet, Repeat until all the bars have been dipped.
  • If desired melt 50g (2oz) plain chocolate in a bowl over a pan of hot water and drizzle or pipe over the chocolate bars. Place in a cool place and allow to set.


Cook's Tips
  • When melting chocolate water is the enemy. If any moisture gets into the melted chocolate it will "seize" and be unusable. To help avoid this make sure the water doesn't boil as this will produce steam. the water should be only just simmering.
  • When you remove the bowl from the pan wipe the base dry with a tea towel.
  • Do not be tempted to lick your fingers when working with chocolate.
  • For best results use more chocolate than you actually need - I used 600g (1lb 6oz) to make mine. If making bite sized bars you will need more chocolate.
  • Pour unused chocolate onto clean baking parchment and allow to set. Wrap and use for other  chocolate bakes.
In an airtight conatiner in a cool dry place for up to 1 week.
Not suitable for freezing


Calories: 233kcal