Marshmallow slice


Marshmallow is one of my very favourite things – real marshmallow, not the kind you buy in a bag in the lolly aisle of the supermarket. There’s something about the softness, texture and melt-in-your-mouth nature of it that takes me straight to my happy place.

But while Kevin likes homemade marshmallow, he’s not such a big fan – he’d much rather I made something ‘more substantial’ like biscuits, cupcakes or a slice… basically something that will fill the gap in the gaping hole he calls a stomach.

Marshmallow slice is the perfect compromise for us – he gets a stomach filling slice, while I get a thick layer of spongy marshmallow; win-win! In my mind marshmallow slice isn’t marshmallow slice unless it’s a pretty shade of pink – there’s something about it that screams happiness and fills me with nostalgia for weekend visits to the bakery for a treat. Finish the slice with a layer of hundreds and thousands and you’ve got something pretty magical on your hands.

Luckily marshmallow slice is nice and simple to make – all you need is a good shortbread slice base and a reliable marshmallow recipe to use at the topping. After much hunting, fiddling and perfecting I am very pleased to have fail-proof, delicious recipes for both in my arsenal so combined them to make what is quite possibly the best marshmallow slice recipe

The shortbread base is wonderfully easy to make – it’s truly as simple as tossing all the ingredients (and there aren’t many) into a bowl and mixing them into a dough. Pop it in a lined pan, bake for 15 minutes and you’re done! It can’t get much easier than that.

Shortbread, marshmallow and sprinkles…what’s not to love? This slice is soft, sweet and delicious, with the marshmallow dissolving in your mouth while the shortbread crumbles at the slightest bite – exactly what you want it to do! I hope you like this recipe as much as I do.


Makes approx 70 squares



  • 300g butter, softened
  • 150g caster sugar
  • 150g fine semolina
  • 300g plain flour


  • 500g sugar
  • 4 tsp glucose syrup
  • 2 Tbsp gelatine powder
  • 2 egg whites
  • 2 tsp peppermint essence
  • Red food colouring
  • Sprinkles (optional)



  1. Preheat oven to 170 degrees Celsius. Line a lamington pan with baking paper.
  2. Place all ingredients in a large bowl and mix until a smooth dough forms.
  3. Press into prepared pan. Place in oven and bake for 15-20 minutes or until lightly golden.
  4. Remove from oven and allow to cool in pan.


  1. Place 200ml of water in a bowl and sprinkle with gelatine. Set aside.
  2. Place sugar, glucose and 200ml of water in a large saucepan. Place on low heat and stir until sugar is dissolved.
  3. Increase heat to medium-high and insert sugar thermometer. Boil for 3-5 minutes until the mixture reaches 120 degrees Celsius.
  4. Remove from heat and carefully add gelatine mixture. Whisk until gelatine dissolves and no lumps remain.
  5. Place egg whites in a large bowl and beat with whisk attachment on high until foamy. Gradually add hot sugar syrup while mixing.
  6. Continue to beat on high until white and glossy – about 5 min with stand mixer, 10 with hand mixer. Beat 1-2 drops red food colouring through mixture.
  7. Pour over prepared shortbread base and leave to set (approx. 24 hours).
  8. Top with sprinkles and cut into slices.

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  • Alison

    I am curious as to what is that clear layer between the marshmallow and the base?

    • Kirsten

      Hi Alison! I was in a bit of a hurry with this one so had to layer on the marshmallow before the base was completely cool, which caused a bit of the marshmallow to absorb into the top of the shortbread – it still stayed beautifully crisp though! It shouldn’t happen if you cool the shortbread entirely before topping with marshmallow :)