Why you’ll love it
Hello Biscoff lovers! This Biscoff millionaire shortbread is just like a classic millionaires shortbread (also known as caramel slice) but with an added kick of the wonderfully spiced Biscoff flavour.
Aside from it’s Biscoff flavouring, the main difference between this Biscoff traybake and the classic millionaires shortbread is that Biscoff biscuit base instead of the usual shortbread base. It’s made using Lotus Biscoff biscuits, just ground to crumbs then mixed with butter. So simple, no mixing dough and all the Biscoff flavour.
The homemade caramel layer is so easy to cook right on the stove top. It’s poured over the Biscoff biscuit base before being topped with chocolate and it sets to perfectly soft and gooey but not runny. I give loads of tips here on making sure your caramel is the right texture, so if you read nothing else before heading to the recipe, read my notes on making the caramel.
First up, let’s clear up all the names. Millionaires shortbread is a slice of layers of cookie, caramel and chocolate. Where I live, it’s more commonly known as caramel slice and in some countries a slice is a traybake. So this can be called whatever works for where you live; Biscoff millionaires shortbread, Biscoff caramel slice or Biscoff traybake.
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Ingredients you’ll need
This Biscoff millionaire shortbread takes just 7 ingredients. Don’t be scared off by the ingredients list in the recipe below – some are just typed out a second time to show the correct quantity for their layer.
Jump to the recipe for full ingredients and instructions.
- Lotus Biscoff biscuits: Biscoff cookies or biscuits are super crunchy little spiced biscuits. Featuring cinnamon heavily, it also includes things like nutmeg and cloves.
- Lotus Biscoff spread: A type of cookie butter, I use the Lotus Biscoff brand which is creamy and spicy and so luscious.
- Butter: Stick to unsalted butter for this one so you can control the salt level. If you only have salted on hand, just leave out the extra salt the recipe asks for.
- Sugar: Some brown sugar goes into the caramel filling to assist with colour and flavour.
- Sweetened condensed milk: An absolute classic ingredient of millionaires shortbread is sweetened condensed milk. It adds the sweetness we need plus creaminess and turns into the most amazing stovetop caramel.
- Chocolate: Grab your favourite milk chocolate here. I don’t like using cooking chocolate as I don’t like the flavour as much as a good eating chocolate.
How to make Biscoff millionaires shortbread (step-by-step)
This Biscoff millionaires shortbread is seriously simple. You’ll need a food processor for the biscuit base (or a blender of some kind), a heavy based stainless steel saucepan for the caramel and just a microwave safe bowl for the chocolate. The slice is set in an 8 inch square baking pan.
Jump to the recipe for full ingredients and instructions.
- Make the base: Start by blitzing the biscuits / cookies to crumbs in a food processor (photo 1) then add melted butter and salt and blitz again to combine. Pour it all into a lined 8 inch square baking tin and press it down firmly all over (photo 2). Chill the base until you need it. If you don’t have a food processor, you can just place the biscuits in a large ziplock bag and use a rolling pin to gently bash them to crumbs.
- Make the Biscoff caramel: The caramel layers starts out as a normal caramel but is then spiked with a little Biscoff spread at the end.
First melt butter then add brown sugar and dissolve over heat (photo 3). Now add the condensed milk (photo 4) and bring to low bubble.
- Let it bubble away for about 5-7 minutes and you’ll notice it goes from a kind of beige colour to a more golden caramel colour (see the difference between photos 4 & 5) and becomes quite thick. It’s ready!
Stir in the Biscoff spread (photo 6) and a little salt then pour it over the biscuit base (photo 7, below). Level it out and chill in the fridge for 15 minutes.
- The chocolate topping: Now simply melt some chocolate in the microwave. Just do this in 30 second increments and stir really well between each until it’s just 90% melted. Stir it to melt the rest of the way. This is so you don’t overheat the chocolate. Pour the chocolate over the caramel layer, then drizzle over some Biscoff spread and swirl it through (photo 8).
Let your Biscoff caramel slice set for a good couple of hours or up to 3 days ahead.
- Keep the heat between low and medium. If you overheat the caramel, you risk it burning and/or crystallising (becoming gritty).
- Use a heavy based stainless steel saucepan – this allows the heat to disperse more evenly.
- Don’t cook it for too long – if you go past the nice thick stage to super thick, you’ll end up with fudge. Still delicious but not the soft, gooey caramel we’re after here.
- Overcooking can also cause the caramel to crystallise.
- Using a thermometer will guarantee caramel perfection – you want the temperature of the caramel to reach 110C / 225F.
Billionaires shortbread has a layer of salted caramel instead of regular sweet caramel.
Millionaires shortbread is believed to have originated in Scotland however it’s now loved the world over. In Australia, it’s known more commonly as caramel slice.
Biscoff cookies are based on the speculoos cookie originating in Belgium. It’s a crisp, buttery cookie with a combination of warming spices like cinnamon, nutmeg, cloves, ginger and cardamom.
Just like Biscoff cookies, the flavour of Biscoff spread is based on the Belgian speculoos cookie. Buttery with warming spices like cinnamon, nutmeg, cloves, ginger and cardamom.
Mainly because the base is just a combo of biscuits and butter, store the Biscoff millionaires shortbread in the fridge in an airtight container. This will just keep the base firm so that it doesn’t just fall apart. It can be eaten straight from the fridge or you can let slices come to room temperature – the caramel won’t ooze, sitting at room temperature.
The best way to slice millionaires shortbread is after letting it sit at room temperature for 20 minutes or so, so the chocolate isn’t super hard. If you’re impatient (like me) just use the warmed blade of a sharp knife to score through the cold chocolate, before wiping it off and cutting all the way through.
Can you freeze millionaires shortbread? This Biscoff millionaires shortbread can be frozen for up to 3 months. It’s best to cut it into slices first, then wrap them individually before storing in an airtight container.
Did you try this Biscoff millionaires shortbread recipe?
Leaving a rating and comment below the recipe is so helpful!
Biscoff Millionaires Shortbread
BISCOFF BISCUIT BASE
- 250 g Lotus Biscoff biscuits (9oz)
- 100 g unsalted butter (3 ½ oz)
- ¼ teaspoon salt
- 125 g unsalted butter (4 ½ oz)
- ½ cup light brown sugar (100g / 3 ½ oz)
- 1 tin sweetened condensed milk (397g / 14oz)
- 2 tablespoons Lotus Biscoff spread (notes 1)
- ¼ teaspoon fine sea salt
- 250 g milk chocolate, roughly chopped (9oz)
- 1 tablespoon Lotus Biscoff spread
For best results, always weigh ingredients where a weight is provided
- Line a square 8 inch baking pan with baking paper.
- FOR THE BISCOFF BASE:Blend the Biscoff biscuits to crumbs in a food processor. Add melted butter and salt and process to combine.
- Pour the crumb mixture into your prepared pan and use a cup measure or glass to assist you pressing it down well into a firm, flat base. Chill until required.
- FOR THE BISCOFF CARAMEL:Over low-medium heat, melt the butter in a heavy based stainless steel saucepan.
- Add the brown sugar and stir until dissolved and fully combined with the butter over low-medium heat. If you use a rubber spatula, you’ll be able to easily feel when the grittiness is almost gone, that’s the right time to go to the next step. Or tilt your pan and you shouldn’t see sugar crystals hanging behind.
- Stir in the sweetened condensed milk. Increase the temperature to just below medium and stir slowly but constantly until you see bubbles appearing. Keep stirring constantly for a further 5-7, until the mixture has turned from beige to golden and thickened. It should be 110C / 225F on a thermometer if you have one handy.
- Remove the caramel from the heat and quickly but carefully stir in the 2 tablespoons of Biscoff spread and salt.
- Pour the Biscoff caramel over the chilled cookie base and tilt slightly to level out.
- Chill at least 15 minutes before adding the topping.
- FOR THE TOPPING:Melt the chocolate in a microwave-safe bowl in the microwave in 30 second increments, stirring very well between each (so you don’t overheat it) until about 90% melted. Stir, allowing the residual heat to melt the remaining chocolate.
- Heat the remaining 1 tablespoon of Biscoff spread in the microwave for 15-20 seconds until runny.
- Pour the melted chocolate over the caramel, then drizzle over the Biscoff spread. Run a knife through it to swirl it around being careful not to dig into the caramel layer.
- Chill for a further 1-2 hours until set.
- Please take a moment to leave a comment & rating. It's appreciated and so helpful.
- Tablespoons: I use a standard Australian 20ml tablespoon (equal to 4 teaspoons). Many countries use a 15ml tablespoon (equal to 3 teaspoons). Check your and adjust accordingly.
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