Espresso millionaire shortbread bars take a crunchy, buttery base, top it with a rich espresso caramel filling, then cover it with dark and white chocolate topping. Sounds pretty great, huh? They look gorgeous on a cookie platter, too.
What’s not to love about a layer of buttery, crumbly shortbread slathered with espresso caramel and topped with decadent chocolate? These bars are a delicious British classic at heart. Here I’ve included espresso powder in the caramel layer which, despite being only one-ingredient addition, totally transforms these millionaire bars.–Emma Duckworth
Espresso Millionaire Shortbread Bars FAQs
If your caramel separates, remove it from the heat and whisk vigorously until it recombines. Separation occurs because there has been uneven heat and the dairy fat has melted too quickly. Just keep stirring!
This recipe actually makes an extra-thick layer of caramel. If you prefer a thinner layer, halve the caramel ingredients.
Caramel needs to reach a minimum of 225℉ to set. If you undercook it it likely won’t set. A sugar thermometer makes things a lot easier but if you don’t have one, make sure the caramel starts to pull away from the edges of the pan and is really thick before removing it from the heat.
Espresso Millionaire Shortbread Bars
For the shortbread
- 2/3 cup (5 1/3 oz) unsalted butter at room temperature, plus more for the pan
- 1 2/3 cups all-purpose flour
- 1/3 cup granulated sugar
- 1 large egg yolk
- 1 teaspoon vanilla extract
- 1/2 teaspoon salt
For the espresso caramel
- 2 cans (14 ounce) full-fat condensed milk
- 2 sticks (8 oz) unsalted butter
- 1/2 cup firmly packed light brown sugar
- 1/2 cup golden syrup
- 2 teaspoons espresso powder
- 1/2 teaspoon salt
For the chocolate layer
- 1 2/3 cups coarsely chopped 70% dark chocolate
- 2 tablespoons (1 oz) unsalted butter
- 1/3 cup chopped white chocolate for feathering
Make the shortbread
- Preheat the oven to 350°F (180°C).
- Butter a 9-by-9inch (23-by-23cm) baking pan and line with parchment paper. Allow the parchment paper to hang over the sides to make it easier to lift the shortbread out once cooked.
- In the bowl of a stand mixer fitted with a paddle attachment, combine the flour, butter, sugar, egg yolk, vanilla, and salt and beat on medium speed until combined and a dough starts to form.
- Tip the dough into the prepared pan and using your hands, press the mixture into the pan until totally level. Using the base of a measuring cup or glass might help to level at the end. Prick the base all over with the tines of a fork.
- Bake until golden, 20 to 23 minutes. Remove the pan from the oven and allow it to cool completely.
Make the espresso caramel
- In a medium saucepan over low heat, combine the condensed milk, butter, brown sugar, golden syrup, espresso powder, and salt and heat until the sugar has dissolved and the butter has melted, 5 to 8 minutes.
- Increase the heat, and bring the mixture to a boil, stirring continuously until the caramel reaches a temperature of 225°F (107°C), turns golden brown, and thickens to a soft fudge consistency, 5 to 10 minutes.
- Pour the caramel onto the cooled shortbread base, level with an offset spatula, and refrigerate until set, about 1 hour.
Make the chocolate layer
- In a bowl set over a pan of barely simmering water, melt the dark chocolate and butter, ensuring the bottom of the bowl doesn't come into contact with the water.
- Once melted and glossy, pour the chocolate mixture over the caramel.
- In another bowl set over barely simmering water, carefully melt the white chocolate. Alternatively, melt the white chocolate in the microwave in 20-second increments. Watch closely, as white chocolate can seize quickly.
- Spoon melted white chocolate into a small piping bag and pipe horizontal straight lines about 1/4 inch (6 mm) apart over the dark chocolate. Score the lines using a skewer by dragging it up and down the top of the chocolate, perpendicular to the lines that you piped.
- Chill in the fridge until completely set, at least 1 hour or overnight. Remove from the baking pan using parchment paper.
- Cut into slices or squares using a sharp, hot knife, wiping between each cut. The espresso millionaire shortbread bars can be stored at room temperature in an airtight container for up to 1 week.
Recipe Testers’ Reviews
These espresso millionaire shortbread bars were a big hit in my house. They were the perfect treat to enjoy while watching the new season of Great British Bake Off! They look very impressive with the layering and feathering but are mostly easy to make.
I had a bit of trouble with the caramel, but it came together in the end. The shortbread base is wonderfully buttery and crumbly (this was my favorite part!), and the caramel has a surprising depth thanks to the espresso powder. I halved the caramel and was happy with the thickness of that layer.
The addition of espresso to these millionaire shortbread bars did just what I wanted it to. It cut the sweetness level a bit and gave the bars a nice mocha flavour.
I only made half the caramel which is the perfect amount for us. I would prefer a slightly thinner chocolate layer but I’m the only one that does. I couldn’t get my white chocolate to melt but that was my fault as I only had chips on hand that apparently are designed not to melt to keep their shape in cookies. They may not be as pretty without the feathering but they are just as delicious. Be prepared for 1.25 to 1.5 hours per layer for the cooling and setting.
Originally published November 26, 2021