Sourdough Millionaire’s Shortbread
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Whether you call these caramel slice, caramel shortbread, or, my favorite, millionaire’s shortbread–you’re going to be obsessed with these! The bottom layer is a sourdough shortbread cookie base, next is the caramel layer, and the top is a chocolate ganache. Sprinkle a bit of coarse salt on top for the most delectable dessert.
These caramel bars have been on my mind for months–MONTHS, I say! But I kept putting the recipe on the back burner until I signed up to bring a dessert for a homeschool meetup. I figured the occasion would be the perfect excuse to do some recipe testing and make these bad boys.
And oh. my. gosh. These sourdough millionaire’s shortbread bars are the richest, most delicious dessert! I’m a huge chocoholic; the only thing that could make a chocolate dessert better is adding caramel.
The base of these bars is dessert enough. The perfect buttery, flaky, shortbread texture (and a lovely way to use up sourdough discard). The next layer is a gooey caramel center, then the bars are topped off with a simple two-ingredient chocolate ganache (that I microwaved!!).
They’re simple to make and will absolutely be a hit at your next gathering.
Looking for other sourdough desserts? Check these out!
- sourdough s’mores cookies
- sourdough brown butter maple cookies
- sourdough lemon cake
- sourdough key lime donuts
- peach upside down ricotta cake
Ingredients
Step-By-Step Instructions
Start by preheating your oven to 350°F (175°C) and lining a 9×9-inch pan with parchment paper. Leave a bit of overhang to help lift the bars out later.
Whisk the flour, sugar, and salt in a large mixing bowl. Cube or grate the butter and add it to the bowl. Add in the sourdough discard until fully incorporated. Mix until combined (it’s going to look dry/crumbly, but trust the process!).
Press the shortbread dough evenly into the bottom of the prepared pan, making sure to get it into the corners.
Bake until the edges are lightly golden. Once baked, let it cool completely before adding the caramel layer. I poked holes in the shortbread here, but after testing again, this isn’t necessary!
In a saucepan, combine sweetened condensed milk, maple syrup, brown sugar, and butter.
Cook the mixture over medium heat, stirring constantly. It will start to thicken and turn a deeper caramel color after about 10 minutes—don’t rush this step!
Once it reaches a thick, golden consistency, remove it from the heat and stir in a splash of vanilla. Allow it to cool for about 15 minutes before pouring over the shortbread.
Pour the caramel over the cooled shortbread base and spread it into an even layer.
Allow the caramel to set at room temperature or speed it up by chilling in the fridge.
Add chocolate chips and heavy cream to a microwave-safe bowl.
Microwave in 20-second intervals, stirring in between, until the ganache is smooth and glossy. Be careful not to overheat or let the chocolate seize.
Pour the melted ganache over the caramel layer and use an offset spatula to spread it evenly.
Place the pan in the fridge and let the bars chill until the ganache is fully set.
Use the parchment paper to lift the bars out of the pan in one piece. Top with coarse salt if desired.
Slice into squares using a sharp knife. For extra clean cuts, warm the knife under hot water and wipe it dry between slices.
Tips for Making These Sourdough Millionaire Shortbread Bars the Best!
- Take time between each layer. Let the shortbread cool as you make the caramel sauce. Allow the caramel sauce to cool before pouring it over the shortbread. Pop the bars in the fridge so the caramel can set before you make and pour the ganache over it. Finally, let the bars chill in the fridge for 1-2 hours before serving.
- For clean slices, first make sure to chill the bars in the refrigerator. When it’s time to slice them, run a sharp knife under hot water and then wipe it dry before slicing into the bars.
- Chocolate ganache seized? Have no fear! If you accidentally microwaved the chocolate ganache too long, you can bring your chocolate ganache back to life. Add a tablespoon of very hot water to the ganache and whisk. If necessary, add another tablespoon of hot water.
If you love these bars, you’ve gotta try these sourdough sugar cookie bars!
Sourdough Millionaire’s Shortbread
Ingredients
For the Shortbread Base:
- 1 ½ cups all-purpose flour
- ½ cup granulated sugar
- ¼ teaspoon salt
- 12 tablespoons salted butter softened
- ½ cup sourdough discard unfed, at room temp
For the Caramel:
- 14 oz 1 can sweetened condensed milk
- ¼ cup maple syrup
- ½ cup brown sugar packed
- 11 tablespoons salted butter
- 1 teaspoon vanilla extract
For the Chocolate Ganache:
- 1 ½ cups semi-sweet chocolate chips
- ¼ cup heavy cream
- 1 teaspoon coarse salt optional
Instructions
Make the Shortbread Base
- Preheat your oven to 350°F (175°C). Line a 9×9-inch baking pan with parchment paper, leaving a slight overhang for easy removal.
- In a mixing bowl, whisk together the flour, sugar, and salt. Cube or grate the butter and add to the mixing bowl.
- Pour in the sourdough discard. Mix until combined (it's going to look dry/crumbly, but trust the process!).
- Press the dough evenly into the bottom of the prepared pan.
- Bake for 25 minutes, or until the edges are lightly golden. Remove from the oven and allow to cool completely. In the meantime, make the caramel sauce.
Make the Caramel
- In a medium saucepan, combine the sweetened condensed milk, maple syrup, brown sugar, and butter.
- Cook over medium heat, stirring constantly, until the mixture thickens and turns a deep caramel color—this takes about 8–10 minutes. Be patient and stir continuously to prevent burning.
- Once thick and bubbling, remove from heat and stir in the vanilla extract. Allow the caramel to cool for about 10-15 minutes before you pour it over the shortbread.
- Pour the caramel over the cooled shortbread and smooth it out with a spatula.
- Let the caramel set at room temperature or place it in the fridge for about 30 minutes for a quicker setting.
Make the Chocolate Ganache
- Add the chocolate chips and heavy cream to a microwave-safe bowl.
- Microwave in 20-second increments, stirring well between each interval. Watch closely to avoid overheating or seizing the chocolate. Stop when the ganache is smooth and glossy.
- Pour the ganache over the cooled caramel layer and spread evenly with an offset spatula.
Chill and Serve
- Refrigerate the bars for at least 1–2 hours, or until the chocolate is fully set.
- Use the parchment overhang to lift the bars out of the pan. Slice into squares with a sharp knife, wiping between cuts for clean edges.
Notes
- For cleaner slices, use a hot knife (run under hot water and wiped dry).
- Store in an airtight container in the fridge for up to 1 week or freeze for longer storage.
These Millionaire Shortbread Bars are so rich and perfect for family gatherings, barbeques, and holidays!