Guinness chocolate brownies with Baileys buttercream frosting
- Lucy Lord
- Mar 13
- 2 min read

A malty sweetness and deep, rich colour, Guinness is the perfect match for chocolate brownies. It's gently simmered to a reduction before being folded through the batter, adding a delicious roasted malt flavour and fudgy texture. These brownies are delicious on their own but I love pairing them with this velvety smooth Baileys buttercream for a luxurious, boozy kick.
Total time to make : 1 hour Time to prep : 30 minutes
Time to bake : 30 minutes
Servings : 16
Ingredients
440ml Guinness 180g butter 210g dark chocolate (70% minimum) 120g plain flour 1 tsp salt 240g caster sugar 1 tsp vanilla extract
3 eggs
Baileys Buttercream frosting 160g butter, softened 420g icing sugar Pinch of salt 1⁄2 tsp vanilla extract
120ml Baileys
Method
Pour the Guinness into a medium saucepan over a medium heat and bring to a gentle simmer. Simmer the Guinness for 20 minutes until the liquid has reduced by about three-quarters, then pour into a bowl and set aside to cool slightly.
Pre-heat a fan oven to 180°C. Grease and line a square 8x8 inch (20cm) baking tin with baking paper.
Using the same medium saucepan (no need to wash it) gently melt the butter and dark chocolate together over a low heat, stirring to mix. Remove from the heat when they are almost melted as they will continue to melt together off the heat.
In a large mixing bowl, add the flour, salt and sugar together, stirring to mix. Pour in the melted butter and chocolate and fold together until nearly combined. Add in the eggs in, one at a time, mixing the batter together in between. Finally, add in the vanilla and pour in the reduced Guinness liquid, folding everything together until combined.
Pour the batter into the prepared baking tin and bake in the oven for 30 minutes until the outside of the brownies is set but the middle still has a slight wobble. The brownies will continue to bake once they are out of the oven and once cooled will have a soft and fudgy centre.
To make the Baileys buttercream frosting, use an electric mixer to beat the butter for 2 minutes until light and fluffy. Add the icing sugar, a few spoonfuls at a time, mixing in between until all the icing sugar has been added. Add in the salt and vanilla, then gradually pour in the Baileys until the consistency of the buttercream is a soft and spreadable but it still holds its shape (similar consistency to toothpaste).
Spoon or pipe the buttercream onto the cooled brownies to frost them.
These are best served chilled, so keep them in the fridge and remove 30 minutes before serving.
Good to know:
Store baked frosted brownies in an airtight container in the fridge for up to 3 days.
Store baked unfrosted brownies in an airtight container at room temperature for up to 5 days.
Unfrosted, baked brownies freeze really well if you have extras or want to make these ahead of time. Simply wrap the brownie (as a whole square or individual squares) tightly in cling film and store in an airtight container or ziplock bag in the freezer for up to 3 months. Defrost at room temperature overnight before frosting or serving.