Salted caramel & peanut butter billionaire’s slice

Salted caramel & peanut butter billionaire’s slice

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(4 ratings)

Prep: 45 mins Cook: 55 mins Plus 4 hrs chilling

More effort

Cuts into 15 big slices or 20 smaller ones
This popular shortbread bake is placed in a whole new league with the addition of an extra layer of indulgence plus a salted toffee topping

Nutrition and extra info

Nutrition: per slice (20)

  • kcal502
  • fat31g
  • saturates16g
  • carbs48g
  • sugars36g
  • fibre1g
  • protein8g
  • salt0.7g
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For the base

  • 225g butter, chopped into cubes, plus a little for greasing



    Butter is made when lactic-acid producing bacteria are added to cream and churned to make an…

  • 140g unsalted peanut, toasted and cooled
  • 225g plain flour
  • 50g cornflour
  • 85g golden caster sugar

For the peanut butter layer

  • 140g butter



    Butter is made when lactic-acid producing bacteria are added to cream and churned to make an…

  • 225g smooth peanut butter
  • 140g icing sugar

For the salted caramel layer

  • 2 X 397g cans Carnation caramel



    This is white, granulated sugar melted until it browns, after which it sets clear and hard when…

  • 1½ tsp flaky sea salt or ½ tsp fine sea salt

For the chocolate-toffee topping

  • 3 x 100g bars dark chocolate, broken into small pieces
  • 140g soft dairy toffee
  • 3 tbsp milk



    One of the most widely used ingredients, milk is often referred to as a complete food. While cow…

  • ½ tsp flaky sea salt


  1. Heat oven to 180C/160C fan/gas 4. Grease and line a 20 x 30cm rectangular cake tin with baking parchment – the best way to do this is with 2 long strips of parchment. Put the ingredients for the base in a food processor and blitz until it starts to clump together – don’t worry if the peanuts are still a little chunky, they will add a lovely texture. Tip onto your work surface and knead briefly to bring together as a dough. Press the dough into the base of your tin in an even layer. Bake for 25 mins until golden, then set aside to cool.

  2. To make the peanut butter layer, melt the butter and peanut butter in a small pan and mix until smooth. Sieve the icing sugar into a bowl, then pour in the hot butter mixture and stir to combine. While the mixture is still warm, pour over the base and smooth out with a spatula. Chill for 2 hrs until set.

  3. To make the caramel layer, put the caramel and salt in a pan, bring up to the boil and simmer vigorously for 2-3 mins, whisking continuously, until the colour darkens a shade or two and the caramel thickens slightly. Leave the caramel to cool for 20 mins (see tips, below). Once cooled, pour it over the peanut butter layer and return to the fridge for a further 2 hrs.

  4. Melt the chocolate in a heatproof bowl set over a pan of barely simmering water. Meanwhile, put the toffees and the milk in a small saucepan and gently heat. They will clump together and struggle to melt at first, but keep heating and eventually they will turn into a runny toffee sauce.

  5. Remove the tin from the fridge and pour the chocolate over the salted caramel layer, tipping the tin to spread the chocolate over the surface. Use a spoon to quickly drizzle the caramel over the chocolate in a thin loopy pattern (or see tip, below). If the toffee starts to get too thick, add a splash more milk or cream and pop it back on the heat until runny. Sprinkle over the sea salt flakes and put the tin back in the fridge to chill for 2 hrs before slicing.

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Comments, questions and tips

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Comments (10)

kateab's picture

Do you really have to specify a Nestlé branded item in your ingredients? Are you even aware that they are the most boycotted brand on the whole world? Read the Baby Milk Action website for details.

sllyst's picture

These were my idea of absolute heaven. Even my partner loved them and he doesn't like peanut butter! Worth any effort for me.

hilaryys's picture

My daughter made this but I was in the kitchen - rather a long haul with all the chilling times and, despite following the tip, still not easy to cut. Don't be tempted to melt the chocolate in advance - it needs to be quite warm so that it doesn't set quickly when you put it onto the chilled caramel layer. Delicious in its own way and very rich but, d'you know what, despite really liking peanuts, I think I prefer the original!!

boobruce-smith's picture

This bake did take the whole day to do but the outcome was worth it.
You have to be patient but the salted caramel and the nuts are a perfect combo, especially when a small slice is served next to coffee.
I also found that despite following the tip on cutting the chocolate cracked however this did not effect the taste and the guests loved it.

katieburr1's picture

I have made this several times and the outcome is great, even though I think too much will kill you! I alway make my own caramel with butter, sugar and condensed milk. When the chocolate goes on the top I leave it to set a little then cut the slices when it's still soft. When it's fully set you can go over the lines again and it doesn't break up. I've got a batch in the fridge at the moment!

nkkingston's picture

I halved everything and used a rubber mould. Everything came out perfectly (if not quite as pretty as the picture!) and it went down really, really well at work! I left it out for fifteen minutes before cutting, as one of the tips recommends, and it cut just fine with a really sharp knife.

fallenstar27's picture

My experience was exactly as mmsanderson's. Followed the recipe and very rarely have any problems baking. My caramel did not set, guess I was too worried of burning it - will need to buy thermometer if I want to make more caramel recipes. And the chocolate layer (and caramel layer) were far too thick. Wasted an entire evening making it (because there are 2x two hour cooling periods) then when I came to cut it, the caramel was runny and the chocolate shattered, couldn't even serve it under a 'rustic' pretense. Was genuinely gutted. I would not recommend this recipe to anyone, you could find others out there.

tr28acy's picture

Hi did you heat your knife before cutting? That's what I do when making caramel cake. Hope this helps.

linerw's picture

I agree with Melanie, I followed the recipe to the letter but when I came to cut the finished 'slab' the chocolate layer just shattered and the whole thing looks a mess! Luckily it's a present for Father's Day as I couldn't serve it to anybody else and I know it tastes great as I tried a piece but its a shame the overall look is ruined. Also it took all day to make and was a bit of an epic...he'd better appreciate it!

mmsanderson's picture

Despite following the instructions to the letter and being an experienced baker my slices completely shattered with the caramel layer being too runny. I would make the shortbread and chocolate layers slightly thinner and have a thicker peanut butter layer.

Very disappointed.

Questions (2)

somethinggood's picture

Please help me!! Does it really mean putting sea salt on top of a sweet pudding??? i have never mixed salt with sweet before!!!

goodfoodteam's picture

Hi there, thanks for your question. Yes, that's right, a small amount of salt complements the sweetness of the caramel and, of late, it's quite common for salt to be included in dessert recipes. Do try it, it's very good!

Best wishes, BBC Good Food team

Tips (1)

dimplechops1986's picture

I haven't tried this myself BUT my partner, who sliced the bake first time round, found the chocolate still cracked despite bringing up to room temp. We found cutting into 20 still made quite big slices so I asked him to cut them in half again(!!!) this time he turned the slices chocolate side down and the choc didn't crack! I can only think this is because by the time you get to the choc, all the squishy layers have been sliced so you can appt maximum pressure to the choc which will be supported by the chopping board.

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