The best Millionaire Shortbread Recipe! Buttery shortbread, smooth caramel and a layer of chocolate come together to make the most delicious caramel shortbread recipe ever. A great bar to feed a crowd or to include on your Christmas cookie tray!

These Millionaire Shortbread Bars are one of the most delicious desserts in my repertoire.  Buttery shortbread, smooth caramel and a layer of chocolate come together to make a sweet treat that will blow you away. This caramel shortbread is a great bar to feed a crowd (e.g. take to a potluck or barbecue) or to include on your Christmas cookie tray.

I consider this millionaire shortbread recipe a medium to advanced baking recipe – simply because caramel can be finicky and requires undivided attention as it’s made – but I promise you they are worth every second of your expertise and time. 

Millionaire Shortbread Recipe: Ingredients and Substitutions 

This caramel shortbread recipe is one for advanced bakers, as caramel isn’t easy to make. As such, I don’t recommend making any substitutions. However, we’ll talk about the ingredients and some possible ingredient swaps. 

• Salted Butter. Unsalted butter can be used in place of salted butter, you may just want to increase the salt slightly. 
• White Sugar. Granulated white sugar is the best in this millionaire shortbread recipe – I have also used pure cane sugar. 
• All-purpose flour. I don’t recommend making substitutions for the flour. 
• Fine Sea salt. Regular table salt can be substituted, you may need to decrease the amount by half. 
• Light brown sugar. I do not recommend making substitutions for the light brown sugar – it is critical for the outcome of the caramel. 
• Light corn syrup. The only recommended substitutes for corn syrup (to be used in the caramel) are brown rice syrup and golden syrup (for my UK friends). Do not make any other substitutions or you will run the risk of your caramel setting up. 
• Sweetened condensed milk. You can make your own homemade sweetened condensed milk, however there are no substituions for it in this caramel shortbread recipe. 
• Heavy Cream. In the chocolate topping, heavy cream can be substituted with half and half. 
• Semi-sweet Chocolate. Use any form of chocolate – chips, chopped bars, discs, etc. I prefer semi-sweet or dark, but you can use any variety to suit your tastes. 

How to make Millionaire Shortbread Bars

This millionaire shortbread recipe is really like three recipes in one. As always, we’ll walk through the process step-by-step, and don’t forget to watch the video!

Make the shortbread

The first step in making these millionaire bars is to make the shortbread. It needs ot cool slightly before pouring the caramel layer on top, and the caramel takes a lot of attention to make, so be sure to start by baking the shortbread. 

Prepare the pan

Line a 9×13” baking pan with parchment paper and grease. This is important to ensure you can remove the bars once they are finished to cut easily. 

Make the caramel shortbread dough

In the bowl of a standing mixer, or in a large bowl with a hand-held mixer, cream together the butter and sugar until light and fluffy (about 60 seconds).

Add egg yolk and vanilla and beat until combined.

Add flour and sea salt and beat until the mixture comes together into large crumbs. Don’t over-mix! 

Press the mixture into the prepared pan in an even layer and gently poke the top all over with a fork. Bake in preheated oven for 20-25 minutes, until the sides are lightly golden brown.

Remove the baked shortbread from the oven and set on a wire rack to cool while you make the caramel.

Make the Caramel

Next, make the caramel. This step requires your full attention, so don’t try to multi-task!

Put butter, brown sugar, corn syrup, condensed milk and sea salt in a 4-quart saucepan and cook over medium-low heat until the caramel reaches 225-235 degrees F on a thermometer, stirring frequently. This takes about 45 minutes. Do not rush it.

How to know when the caramel is done

The best way to know the caramel is done is by using a thermometer. Once it reaches 225-235 degrees F you know it is finished.

You will know you’re getting close when the caramel becomes slightly darker brown in color (but it’s still light brown), thickens and pulls away from the sides of the saucepan as you stir. It will also remain solid when removed from the pot and left to cool or put in cold water. When the caramel is finished cooking, remove from heat, add vanilla and stir vigorously.

How to avoid the butter separating from the caramel

Sometimes, as you’re cooking caramel, the butter begins to separate from the mixture. I have never had this happen with this recipe, but it can happen, so here are some ways to avoid separation – and below I give ways to fix it. 

• Use salted butter. Be sure to use salted butter because the salt helps stabilize the caramel.
• Avoid extreme temperature changes. Don’t turn the heat up high in order to cook the caramel faster. 
• Stir constantly. Please don’t walk away – this caramel needs to be stirred often. 
• Melt butter & sugar together. Make sure the butter and sugar melt at the same time in the beginning of cooking. You can chop the butter into smaller pieces to ensure that happens. 
• Use a thick stockpot to avoid uneven heating. 

How to fix caramel if the butter separates

Here are some ways to fix separated caramel, as long as you have not removed it from the saucepan you should be able to save it in one of these two ways: 

• Beat it! If the butter separates from the caramel, remove it from the heat and beat it vigorously un it’s re-incorporated! Then, if it’s not finished cooking gradually heat the mixture over low heat until it’s finished. 
• Add hot water. You can try to add 1 to 2 TBS of extremely hot (boiling) water to the mixture and beat it vigorously to re-combine the ingredients. 

Pour caramel over shortbread & chill

As soon as the caramel is finished, immediately pour over cooled shortbread. Then, place the millionaire bars in the refrigerator or outside on a cold day to cool and for the caramel to set. Chill for about 30-60 minutes.

Make the Chocolate Topping

Once the caramel is firm, make the chocolate topping. In a small saucepan, heat the heavy cream over medium heat until it just begins to bubbles around the edges, but does not boil.

Reduce heat to low, add chocolate chips and whisk until the mixture is smooth and glossy. Remove from heat, add vanilla and whisk to combine.

Pour over caramel & chill

Pour the chocolate topping over the firm caramel and let sit at room temperature or in the refrigerator until the chocolate is set and bars are firm – this takes about 3-6 hours. 

Add sea salt

If desired, once the chocolate is mostly firm but not completely, sprinkle some flaky sea salt over the top of the bars. 

Cut Millionaire Shortbread into square and serve

Once the chocolate is sufficiently firm, cut the millionaire shortbread into squares. They are best when served at room temperature, so I suggest cutting them and waiting a bit to serve them until they have softened slightly. 

How to cut millionaire bars

The best way to cut these millionaire bars is to run a very sharp knife under hot water, wipe dry and then cut. Repeat between each cut, cleaning and warming the knife each time to avoid any crumbs. 

To store

Store these millionaire bars in an airtight container at room temperature for 5-7 days. You can also store them in the refrigerator and they will last a little longer, but you would want to let them sit at room temperature to warm up a bit before serving. 

To freeze

If you’d like to freeze these millionaire bars, here’s how: 

1. Place cut bars on a large baking sheet – not touching. 
2. Freeze for 1 hour, or until hardened.
3. Wrap individually with plastic wrap and place them in an airtight container. 
4. Store in the freezer for up to 2 months. 
5. To thaw: remove frozen millionaire bars from the freezer and let them sit at room temperature until softened enough to eat. 

FAQs about Millionaire Bars

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If you love this recipe, try these

As you know, we take our desserts seriously around here. If you love this caramel shortbread recipe, here are some others I recommend trying!

• Bars: Bars are so much easier to make than cookies (in my opinion) because it’s a spread and bake situation. We love these chocolate peanut butter bars, chocolate chip cookie bars, and these chocolate peanut butter oatmeal bars. 
• Cookies: Some of our favorite cookies include, these double chocolate cookies, the best chocolate chip cookies, oatmeal cookies, and these peanut butter cookies.  
• Check out our roundup of all of our favorite Christmas Cookie Recipes!
• Cake: Everyone needs classic cake recipes in their repertoire. This is the best chocolate cake recipe you’ll ever eat (ever), plus try this banana cake, pumpkin cake, and I can’t forget my favorite – flourless chocolate cake. 
• Brownies. I have so many brownie recipes on my site because they’re my favorite dessert. The best homemade brownies, peppermint brownies, black bean brownies, flourless brownies, fudgy paleo brownies, etc. each one delicious! 
• Candy. Another great addition to a cookie platter is homemade candy. Our homemade almond toffee is the best. Also try these Oreo balls, Chocolate peanut butter balls, and candied pecans or candied almonds.