This Pecan Shortbread Squares with Marshmallow recipe yields plush homemade marshmallow swirled with homemade pecan butter atop a pecan shortbread crust. You could also call these marshmallow pecan pie bars, but they're definitely a "not too sweet" version. I developed them as a take on divinity, a vintage dessert made from whipped egg whites and pecans.
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This is the second installment of my new vintage recipe redo series on social media. I used the textures and flavors of divinity to create something entirely new. My gripe with divinity is that I want more pecan flavor and more substance. With these pecan bars you get the chewy plush feel from the marshmallow, with more pecan and more substance thanks to the toasted chopped pecans in the shortbread crust and homemade pecan butter. The marshmallow recipe is adapted from the Flavor Bender, and I highly recommend reading that entire recipe and blog post for all of the tips for success. A big difference between that recipe and mine, is that I toasted the granulated sugar that I used in the marshmallow to remove that "sickly sweet" factor.
You really would not be able to tell from the recipes on this blog that I used to hate nuts in desserts as a kid. Now, I love the complex flavor they bring to treats like my Chocolate Orange Maple Povitica bread or Carrot Cake Trifle.
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Why you'll love this recipe
- These are chock full of pecan flavor.
- For a marshmallow-based dessert, this one is not too sweet.
- This is a great recipe to use up pecans!
Ingredients
- Pecans flavor the shortbread crust and the pecan butter that gets swirled into the marshmallow. You can use pecan pieces, whole pecans, or pecan halves. Be sure to toast them. See instructions in the notes in the recipe card.
- All-purpose flour is the base of the shortbread. You can also use cake flour.
- Water brings moisture to the marshmallow.
- Granulated sugar sweetens the shortbread, the marshmallows and the pecan butter.
- Unflavored gelatin provides structure and bounce to the homemade marshmallow.
- Corn syrup brings stability to the sugar mixture for the marshmallow.
- Egg yolk adds richness and binds the shortbread crust. I always use large eggs when baking.
- Ground cinnamon flavors the pecan butter.
- Kosher salt and vanilla extract balance the overall flavor of the dessert.
- Unsalted butter brings richness and flavor to the shortbread.
See recipe card below for a full list of ingredients and measurements.
Substitutions and variations
Here's how to customize these pecan shortbread squares with marshmallow to your liking:
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- Brown sugar — replace the granulated sugar with brown sugar in the shortbread crust for a chewier texture.
- Chocolate chips — sprinkle mini chocolate chips in place of, or in addition to, the pecan butter on top of the marshmallows.
- Store-bought pecan butter — feel free to use storebought pecan butter in place of homemade for the swirled top.
- Toasted — Before eating, use a kitchen torch or campfire to torch the marshmallow for a gooey toasted marshmallow top.
- Other garnishes — top with toasted coconut or a thick homemade caramel sauce in place of pecan butter.
- Another flour — you can use all-purpose, cake flour or gluten free flour for the base of the shortbread.
- Half — half the recipe to yield 9-10 slices, and use a 9x9-inch square pan to bake in. I still recommend making the full amount of pecan butter though, as your food processor works better with a larger volume to process.
This recipe has not been tested with any substitutions or variations. If you try any, please let me know how it turned out by commenting below!
How to make pecan shortbread squares with marshmallow
Step 1: Preheat the oven to 350°F. Grease and line a 9x13 pan with parchment paper with overhang. Cream together the room temperature butter and granulated sugar in a stand mixer fitted with the paddle attachment or in a large bowl with a hand mixer. This usually takes 3-4 minutes. Add the egg yolk, vanilla extract and salt and beat to combine. Add the flour and pecans and mix just until no dry streaks of flour remain. Do not overmix. Spread the pecan mixture in the prepared pan with an offset spatula and bake for 20-25 minutes or until golden brown at the edges. Bake time will vary depending on your oven, so keep an eye on it.
Step 2: In the bowl of a food processor, add the roasted pecans (see recipe card notes for instructions on toasting pecans on a baking sheet). Process until smooth, scraping down the sides of the bowl occasionally. My processor took 4-5 minutes, but this can take up to 10 minutes depending on the age and strength of your mixer. With the processor running, add the cinnamon, sugar and salt and mix until incorporated. Remove to a mixing bowl and set aside.
Step 3: Make sure your ingredients are measured out and ready to go, and that you have an instant read or candy thermometer nearby. In the bowl of a stand mixer fitted with the whisk attachment, combine the unflavored gelatin and ½ cup of the water. Stir and set aside to bloom, at least 10 minutes. Meanwhile, in a 2-quart heavy-bottomed sauce pot, combine the toasted granulated sugar, ½ cup of the water and corn syrup. Stir until all of the sugar is moist and then do not stir again. Heat over medium-high until the mixture boils, then cover the pot and lower to medium heat to cook for 2 minutes. Remove the lid and cook until the mixture reaches 245°F. Remove from the heat once it reaches this temperature. Working quickly, turn on the mixer to medium-low speed. Begin to stream in the hot sugar mixture in a small, slow and steady stream along the wall of the mixer bowl. Add the kosher salt and turn the mixer to medium-high, letting it whip for 3-5 minutes. Turn the mixer to high speed and mix for a further 3-5 minutes, until doubled in size, fluffy and smooth.
Step 4: Pour the marshmallow over the cooled baked crust, smoothing with an offset spatula. Working quickly, spoon or pipe on some of the pecan butter in small drips or lines. Use a butter knife or chopstick to swirl it in. You will have pecan butter leftover. Let the marshmallows sit overnight, loosely covered, before slicing into 20 squares using an oiled sharp knife. Clean the knife and re-oil every few cuts to avoid sticking.
Top tips
- Measure pecans after chopping, not while whole or halved.
- Work quickly when spreading the marshmallow in the pan and swirling the pecan butter in. When the marshmallow cools it becomes difficult to make the swirls.
- Check out the full, very detailed marshmallow tutorial from The Flavor Bender to prepare!
Recipe FAQs
Store in an airtight container at room temperature for 3-4 days.
If you attempt to half the pecan butter recipe, your food processor may struggle to process the smaller volume of nuts.
I actually tested this the first time and it was a fail! The moisture from my maple syrup broke the emulsion of the pecan butter and I ended up with a gunky oily mess.
Bagged regular or mini marshmallows wouldn't have a way to stick to the shortbread so I wouldn't recommend this. Marshmallow fluff may work, but it won't "set up" stiff like a homemade marshmallow.
No, I do not recommend this. Parchment paper holds up to the heat of baking and is super nonstick, which is important for marshmallows.
More recipes you'll love
Lastly, if you make this Pecan Shortbread Squares with Marshmallow recipe be sure to leave a comment or give it a rating. I love to see when people make my recipes, so please tag me @youthsweets on Instagram if you post!
📖 Recipe
Pecan Shortbread Squares with Marshmallow
Equipment
Ingredients
Pecan shortbread
- 1 cup unsalted butter room temperature
- ½ cup granulated sugar (83g)
- 1 large egg yolk room temperature
- 1 teaspoon vanilla extract
- 2 ¼ cups cake flour (256g) or all-purpose flour
- ¼ teaspoon kosher salt
- ¾ cup pecans chopped* and roasted** (85g)
Cinnamon pecan butter
- 2 cup pecans roasted** (214g)
- ½ teaspoon cinnamon
- 1 teaspoon granulated sugar more if desired
- Pinch kosher salt
Homemade marshmallow
- 2 cups granulated sugar toasted*** (333g)
- ⅓ cup light corn syrup (108g)
- 1 cup water divided (236g)
- 7 teaspoon unflavored powdered gelatin (22g)
- ⅛ teaspoon kosher salt
Instructions
Do ahead
- Warning: Marshmallows need to sit overnight before slicing to cure. This is a two-day recipe.
- The pecan butter can be made up to 2 days ahead of time and stored in an airtight container at room temperature.
Make the shortbread
- Preheat the oven to 350°F. Grease and line a 9x13 pan with parchment paper with overhang.
- Cream together the butter and granulated sugar in a stand mixer fitted with the paddle attachment or in a large bowl with a hand mixer. This usually takes 3-4 minutes.
- Add the egg yolk, vanilla extract and salt and beat to combine. Add the flour and pecans and mix just until no dry streaks of flour remain. Do not overmix.
- Spread the dough in the prepared pan with an offset spatula and bake for 20-25 minutes or until lightly golden at the edges.
Make the pecan butter
- In the bowl of a food processor, add the roasted pecans. Process until smooth, scraping down the sides of the bowl occasionally. My processor took 4-5 minutes, but this can take up to 10 minutes depending on the age and strength of your mixer.
- With the processor running, add the cinnamon, sugar and salt and mix until incorporated. Set aside.
Make the homemade marshmallow
- Make sure your ingredients are measured out and ready to go, and that you have an instant-read or candy thermometer nearby.
- In the bowl of a stand mixer fitted with the whisk attachment, combine the unflavored gelatin and ½ cup of the water. Stir and set aside to bloom, at least 10 minutes.
- Meanwhile, in a 2-quart heavy-bottomed sauce pot, combine the toasted granulated sugar, corn syrup and ½ cup of the water. Stir until all of the sugar is moist and then do not stir again. Heat over medium-high until the mixture boils, then cover the pot and lower the heat to medium to cook for 2 minutes.
- Remove the lid and cook until the mixture reaches 245°F. Remove from the heat once it reaches this temperature. Working quickly, turn on the mixer to medium-low speed. Begin to stream in the hot sugar mixture in a small, slow and steady stream along the wall of the mixer bowl.
- Add the kosher salt and turn the mixer to medium-high, letting it whip for 3-5 minutes. Turn the mixer to high speed and mix for a further 3-5 minutes, until doubled in size, fluffy and smooth.
Assemble
- Pour the marshmallow over the cooled prepared pecan shortbread crust, smoothing with an offset spatula.
- Working quickly, spoon or pipe on some of the pecan butter in small drips or lines. Use a butter knife or chopstick to swirl it in. You will have pecan butter leftover.****
- Let the marshmallows sit overnight (or at least 6 hours), loosely covered, before slicing into 20 squares using a sharp oiled knife. Clean the knife and re-oil every few cuts to avoid sticking.
Notes
Nutrition
Originally published 05/30/2025.
