Peanut Butter Millionaire’s Shortbread

Millionaire’s Shortbread, which is traditionally caramel and chocolate over a shortbread crust, first began to appear in Australia in the early 1970’s. A million dollars doesn’t go nearly as far these days as it did back then. That’s why I decided to make mine a Billionaire’s Shortbread by adding a peanut butter layer to the classic recipe.

Stack of three bars

Two of my favorite candy bars are Twix and Snickers. During the summer, growing up, I used eat frozen Snickers on the daily. (I was a distance swimmer. I needed the calories! Don’t judge.) I’d eat the chocolate off the sides and the bottom of the bar before eating the rest of the bar. It was weird, I admit it, but I felt it gave you a bar with the perfect ration of chocolate to nuts to caramel to nougat. Again, don’t judge.

And the beauty of Twix is it’s simplicity. Shortbread cookie, caramel, and chocolate giving you the perfect blend of flavors and textures. What’s not to love? When I fly I always buy myself a Twix bar and a bag of Combos (Yes, you read that right. Combos. I have no shame.) Any calories consumed on a plane don’t count, right? Right?

Luckily, I don’t fly that much anymore now that I’m no longer working at a law firm. Otherwise, this habit could be problematic.

Overhead shot of bars on wooden tray

I love this recipe for Peanut Butter Billionaire’s Shortbread because it has everything I love about both candy bars. First, simplicity. Each layer is a classic flavor: buttery shortbread, satiny-smooth caramel, creamy peanut butter topped with straight-up chocolate. By itself each layer is relish, but put them together? You’ve got a dessert thats tastier than the sum of its parts.

Second, like the poor mutilated Snickers of my childhood, it has just the right ratio of chocolate to peanut butter to caramel to shortbread. No one layer outshines the others. Instead, each complements and enhances the other beautifully. Add some chopped peanut as garnish (which I highly recommend) and you’ve taken these bars over the top with the addition of a little crunch.

Bar on white plate with coffee and fork

Enough waxing poetic about candy bars though, let’s talk recipe. These bars have four layers, but each layer is relatively simple to make. If you have young kids or a busy schedule (I’m pretty sure that’s everyone) this is actually a great recipe to make because you can make a layer and then go do something else while that layer cools. Repeat three times and in a few hours your bars are complete.

Bowl of flour and eggs being mixed

Let’s get into how to make each layer. First, layer of shortbread. All it involves is mixing ingredients, spreading it into an even layer, poking with a fork a few times, and it’s ready to cook.

ball of shortbread dough in baking pan
Uncooked shortbread in baking pan

Let it cook and your shortbread layer is complete.

Cooked shortbread in baking pan

Next the caramel layer. This is probably the trickiest layer, but that’s only because you need to get it to a certain temperature. Other than that, it’s dumping ingredients in a pot and heating.

Caramel cooking in pot

Once it’s done, pour it over the shortbread and go yell at the kids for a bit while it cools.

Caramel in baking pan

Third layer? Peanut butter sauce. This one couldn’t be easier. Mix the ingredients together and spread on the caramel.

Ingredients for peanut butter layer in bowl

Finally, the chocolate layer. All that’s required is microwaving chocolate chips. If you can microwave you’re all set. Top it with some reserve peanut butter sauce and chopped peanuts and you’re done.

Close-up of top of bars

After that, they go in the fridge to cool. Use this time to make a to do list for your husband or order those yoga pants you’ve been eyeing.

Once they’re cool, all that’s left is to cut it into bars. My preferred method for getting neat squares is to heat the knife by running it under hot water and then drying it. The heat from the knife helps to cut the bars cleanly.

Bars on wooden tray

Now that they’re cut, call your family to try them. But I recommend you hide some for yourself because they won’t last long.

Stack of three bars

Peanut Butter Billionaire’s Shortbread

  • Author: closeenoughcook
  • Prep Time: 45
  • Cook Time: 45
  • Total Time: 1 hour 30 minutes
  • Yield: approx. 20-24 bars


This recipe takes millionaire’s shortbread and turns it into billionaire’s shortbread with the addition of peanut butter.  It combines the best parts of a Twix and a Snickers and turns them into homemade deliciousness.  Eat just one and you’ll be craving more for days. Don’t say I didn’t warn you . . .

Adapted from The Perfect Cookie by America’s Test Kitchen



Shortbread Crust

2 1/2 cups all-purpose flour

1/2 cup sugar

3/4 tsp salt

2 sticks unsalted butter, melted  

Caramel Layer

1 (14 oz. can) sweetened condensed milk

1 cup packed light brown sugar

1/2 cup heavy cream

1/2 cup corn syrup

1 stick unsalted butter

1/2 tsp. salt

Peanut Butter Layer

6 tbsp packed light brown sugar

2 cups confectioner’s sugar

6 tbsp unsalted butter softened

1 1/3 cup creamy peanut butter

Chocolate Layer  

8 ounces semisweet chocolate chips

1/2 cup peanuts, rough chopped for garnish (optional)


  1. Preheat oven to 350 degrees. 
  2. Make a foil sling in a 13 inch by 9 inch baking dish by placing one piece of tin foil length-wise in the baking pan, making sure to use enough foil that it hangs over the sides of the dish, and a piece of tin foil width-wise in the dish, again making sure to use enough so that it hangs over the sides.  Flatten foil against bottoms and sides as well as in corners to make the foil as flush with the dish as possible.
  3. Combine flour, sugar, and salt in a large bowl.  Stir in melted butter until fully incorporated.  
  4. Place ball of dough in dish and using hands push the dough outwards until the bottom of the dish is fully covered.  As much as possible try to have the shortbread layer be an even thickness.  
  5. Dock the shortbread using a fork at 1-inch intervals.*
  6. Back shortbread approximately 25-30 minutes or until crust is beginning to brown and is firm to the touch. 
  7. Allow shortbread to rest until cool to the touch. 
  8. While shortbread is baking, begin to make the caramel layer by stirring the condensed milk, brown sugar, butter, cream and corn syrup together in a large pot over medium heat.
  9. Cook, stirring frequently, until mixture is between 236 and 239 degrees (approximately 20 minutes).**
  10. When caramel is done cooking, pour over the top of the shortbread and put pan in refrigerator until caramel is cool to the touch. 
  11. While caramel is cooling make the peanut butter layer by combining all ingredients in a medium bowl. 
  12. When caramel has completely cooled, cover with peanut butter layer by dropping spoonfuls of the peanut butter mixture over top the caramel and gently smoothing with an off-set spatula.***  
  13. For the chocolate layer, place chips in a small bowl and microwave, stopping every 15 seconds to stir, until chocolate is almost completely melted (approx. 1 minute).  Take care not to overheat the chocolate.  
  14. Stir chocolate until completely smooth and then pour over the peanut butter layer.  Spread chocolate into an even layer using an offset spatula.  Work quickly as chocolate tends to reharden relatively fast.
  15. Place shortbread in refrigerator for at least 30 minutes. 
  16. If using, warm reserved peanut butter layer and microwave in 10 second intervals until mixture is pourable but runny.  
  17. Using a spoon drizzle warm peanut butter mixture over top of the chocolate layer and garnish with chopped peanuts.  

*”Docking” means to poke holes in a pastry crust so as to allow steam to escape during cooking thus preventing the crust from puffing up.  

** If you don’t have a thermometer handy, you can tell when the caramel is ready by using the cold water test. 236-239 degrees is the “soft ball stage” of candy making which means that when a you drop a bit of the mixture into a glass of cold water it will form a soft malleable ball.  Once the caramel reaches this point it’s done cooking.  Here’s some more information on the cold water test if needed.

***If planning to garnish the top of the bars with peanut butter sauce, reserve approximate three tablespoons of mixture and set aside. 

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