Millionaire Shortbread is a decadent dessert with layers of soft buttery shortbread, rich caramel and a silky-smooth chocolate ganache that melts in your mouth.
Preheat your oven to 180C / 355F (fan off), 160C / 320F (fan on). Spray the bottom of a 22cm / 9-inch square baking tin with oil spray and line with baking paper, leaving some overhang for ease of lifting out later. I used uncoated bulldog clips to keep the paper in place.
Whip butter and sugar - Add your softened butter, sugar, salt, vanilla extract and orange zest (optional) to a medium sized mixing bowl. Use an electric hand mixer or stand mixer fitted with the paddle attachment to cream the ingredients together until pale and lightly creamed together, about 60 seconds. We’re not trying to whip air into the butter.
Add flour to form dough - Add half the flour and use a spatula to mix until a dough forms and no dry ingredients are showing. Then add the remaining dry ingredients and repeat. You want to make sure the dough is mixed well and that there are no dry ingredients showing. Try not to overmix though otherwise you’ll end up with tough cookies without a delicate crumbly and tender texture.
Forming the shortbread layer - Pour the biscuit dough into the tin and use your hands to press as flat as you can. You can even use the bottom of a flat cup or measuring cup to get it perfectly flat for uniform looking biscuits. Be gentle and mindful not to press down too hard otherwise the cookies will be dense.
Baking - Bake for 20 minutes or until lightly golden. Take out of the oven and allow to cool while you make the caramel layer.
Caramel Layer
Syrup - Add the butter, sugar, golden syrup and sweetened condensed milk to a large saucepan and place on medium heat. Gently stir until the mixture is melted and it begins to bubble around the sides.
Cook mixture - Continue stirring the bubbling mixture for 8 minutes over medium heat. It’s important to stir continuously to prevent crystallization or burning. It will darken slightly in color. Take off the heat and add the vanilla and salt and stir until combined.
Set caramel - Pour the mixture on top of the shortbread base. Allow to cool to room temperature, about an hour or until set.
Chocolate
Melt chocolate - Add the cooking chocolate and oil to a heat proof bowl. Double Boiler: add on top of a pot of gently simmering water, making sure the bottom of the bowl isn’t touching the water and stir until melted. Microwave: microwave for 30 seconds at a time, stirring each time until smooth.
To Finish - pour on top of the cooled slice and spread evenly using a spoon or offset spatula. Allow to set in the fridge for 20 minutes.
How to get perfect clean slices - run a large knife under hot water and carefully dry with a towel. Slice into 4 x 4 bars, cleaning the knife, warming it and drying it with each slice. Serve.
Notes
Sweetened Condensed Milk - Use regular, full fat sweetened condensed milk for this recipe, not low-fat or skim.Storage - Millionaire Shortbread can be stored in an airtight container, in the fridge for up to three days.Nutrition – is an approximate and is based on per slice. This recipe makes 16 bars.A note on measurements – This recipe uses weight measurements for the most accurate results. Cup measurements can vary depending on where you are, which affects the precision needed for a recipe like this. Here is where you can learn more about how to measure ingredients using digital kitchen scales.