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    Home » Recipes » Slow Cooker Desserts

    Slow Cooker Marshmallow Brownies

    image of Lucy's face
    Modified: Oct 15, 2025 · Published: May 22, 2014 by bakingqueen74 · This post may contain affiliate links · 6 Comments
    2294 shares
    Jump to Recipe

    Rich, gooey and indulgent, Slow Cooker Marshmallow Brownies are just the best!

    Slow cooker marshmallow brownies on plate.

    The marshmallows melt into the centre of the brownies, making them even more gooey and sticky, then you melt some more marshmallowy on top for a chewy layer to bite through.

    Brownies are the perfect bake to make in a slow cooker, they are fudgy and dense and of course you can forget about them for a couple of hours.

    Line your slow cooker with parchment/baking paper, and add a cloth/tea towel under the lid to catch drips and moisture, and your slow cooker is ready for baking.

    I bake a lot in my slow cooker, in case you hadn’t noticed, there are loads more slow cooker baking ideas and recipes here and in my slow cooker archives.

    Slow cooker marshmallow brownies cut into squares.

    Slow cooker marshmallow brownies taste great and are so easy to bake.

    These are perfect for baking with kids too. Mine really love slow cooker baking and there is much less risk of them burning themselves.

    Ingredients

    Here are the ingredients you will ned for this recipe, get the measurements in the recipe card further down:

    • butter
    • chocolate
    • eggs
    • caster sugar
    • cocoa powder
    • plain flour
    • marshmallows
    Slow cooker marshmallow brownies in a stack.

    Method

    1. Chop the butter and chocolate up into small pieces and put in a bowl. Microwave on high for 1-2 minutes until melted. Allow to cool.
    2. Whisk the caster sugar and eggs together for 3-5 minutes using an electric mixer, until it looks thick and creamy.
    3. Pour the cooled chocolate and butter mixture over the egg and sugar mixture and fold it in gently until completely mixed.
    4. Sieve in the cocoa powder and flour and again fold in gently until completely incorporated, but do not overmix.
    5. Grease and line your slow cooker bowl with grease proof paper.
    6. Pour the brownie batter in.
    7. Add about 6 of the marshmallows, in pieces, on top.
    8. Cook on high for 1.5 to 2 hours or until just set in the centre. See my note below regarding cooking time. 
    9. Half way through, add the rest of the marshmallows on top (the others will have sunk/melted into the brownies).
    10. Allow to cool completely before using the baking paper to remove from the slow cooker.
    Slow cooker marshmallow brownies in squares with chocolate chunks.

    Cut yourself a square and enjoy with a coffee. Share with your friends and work colleagues and you’ll be popular!

    They would be great for a school or workplace bake sale too.

    Slow cooker marshmallow brownies on baking paper.

    More slow cooker desserts

    • Large round scone with chocolate chips cut into triangles.
      Slow Cooker Chocolate Chip Scones
    • Nutella cake with nutella drizzled over it
      Slow Cooker Nutella Giant Scone
    • Slow Cooker Self-Saucing Chocolate Orange Pudding
    • Syrup sponge on a white plate, custard and golden syrup behind.
      Slow Cooker Syrup Sponge

    Recipe

    Squares of marshmallow brownies.

    Slow Cooker Marshmallow Brownies

    Bake delicious chewy marshmallow brownies in your slow cooker
    5 from 2 votes
    Print Pin Rate Save Saved!
    Course: Dessert
    Cuisine: British
    Prep Time: 15 minutes minutes
    Cook Time: 2 hours hours
    Total Time: 2 hours hours 15 minutes minutes
    Servings: 10
    Calories: 283kcal
    Author: Lucy Allen | BakingQueen74

    Ingredients

    • 125 g butter
    • 125 g dark chocolate broken into small pieces
    • 2 medium eggs
    • 150 g caster sugar (superfine sugar)
    • 20 g cocoa powder
    • 60 g plain flour (all-purpose flour)
    • 10 large marshmallows cut in half
    UK Measurements – US Measurements

    Equipment

    oval slow cooker
    oval slow cooker
    mixing bowl
    mixing bowl
    spatula
    spatula

    Instructions 

    • Chop the butter and chocolate up into small pieces and put in a bowl. Microwave on high for 1-2 minutes until melted. Allow to cool.
      125 g butter, 125 g dark chocolate
    • Whisk the caster sugar and eggs together for 3-5 minutes using an electric mixer, until it looks thick and creamy.
      150 g caster sugar (superfine sugar), 2 medium eggs
    • Pour the cooled chocolate and butter mixture over the egg and sugar mixture and fold it in gently until completely mixed.
    • Sieve in the cocoa powder and flour and again fold in gently until completely incorporated, but do not overmix.
      20 g cocoa powder, 60 g plain flour (all-purpose flour)
    • Grease and line your slow cooker bowl with grease proof paper.
    • Pour the brownie batter in.
    • Add about 6 of the marshmallows, in pieces, on top.
      10 large marshmallows
    • Cook on high for 1.5 to 2 hours or until just set in the centre. See my note below regarding cooking time. 
    • Half way through, add the rest of the marshmallows on top (the others will have sunk/melted into the brownies).
    • Allow to cool completely before using the baking paper to remove from the slow cooker.

    Notes

    Note: Timings need to be adapted for your own slow cooker.
    If your dishes often cook quickly, check the brownies after an hour. Watch out for burning.
    If your slow cooker cooks slowly like mine, you might need to extend the time. Mine took 3 hours in a very slow slow cooker!
    Did you try and love this recipe?Then please leave a star rating and comment below to let me know how you got on!

     

    More Slow Cooker Desserts

    • Sliced cake on rack with lemons behind.
      Slow Cooker Lemon Drizzle Cake
    • Top of bread and butter pudding in slow cooker ceramic pot.
      Slow Cooker Bread and Butter Pudding
    • Blackberry crumble in a black slow cooker pot.
      Slow Cooker Blackberry Crumble
    • Slow cooker brownies in pot, covered in chocolate mini eggs.
      Slow Cooker Mini Egg Brownies

    Reader Interactions

    Comments

    1. Rachel says

      December 17, 2015 at 7:27 pm

      My slow cooker burns the outside before the middle is cooked if I use grease proof paper so I got come silicon cake tins and silicon cupcake molds (put paper cupcake cases inside these) now there’s no burning just yummy cakes and brownies.

      Thanks for sharing the recipes. 🙂

      Reply
    2. Jessica Grabaskey says

      February 06, 2015 at 5:02 pm

      Hi, may sound a really silly question but never tried anything like this before… Do I put the lid on the slow cooker or not?

      Reply
      • bakingqueen74 says

        February 06, 2015 at 10:28 pm

        Hi, yes the lid goes on, you can put a tea towel under it if needed to catch the drips and stop the top of the brownies going soggy!

        Reply
    3. amanda says

      January 07, 2015 at 9:35 pm

      I made these tonight but they didn’t turn out so great!followed the recipe, greased and lined the slow cooker pot, cooked on high until middle just set but the sides and bottom ended up burnt and stuck to the greaseproof paper!Any ideas where I went wrong or did I just cook it for too long?Feel if id taken it out sooner to prevent sides burning it wouldn’t have been cooked properly in the middle!!I got stuck into the middle of it with a fork to try it and its so good, lovely and moist and gooey its such a pitty it’s not like that throughout and cant be separated from the paper!!Would love to get these right!

      Reply
      • bakingqueen74 says

        January 07, 2015 at 9:47 pm

        Hi Amanda, it sounds like,your slow cooker cooks very hot, I do find some are hotter than others. I actually have one slow cooker I wouldn’t try this in as I bet it would burn in an instant! What size is your slow cooker? One good way to,stop it getting hot so quickly is to use a silicone pan within the slow cooker, on top of an upturned saucer so something like that. That way it kinds of steams but without the contact to the bottom of the pot to make it burn. If you can see my cream cheese brownies recipe I did that for that recipe, and it worked really well.

        Reply
    4. Munchies and Munchkins says

      August 25, 2014 at 1:23 pm

      Well these sound a bit epic. I may try making my own fave brownie recipe in the sc. Never thought of doing that before.x

      Reply
    5 from 2 votes (2 ratings without comment)

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    Hi, I'm Lucy! I'm a slow cooker addict, food blogger and also a busy working mum of two. I hope you'll enjoy the recipes I create and post which are perfect for busy families.

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