Perfect for a picnic or family gathering, these salted peanut bars combine a chewy brown sugar crust, a gooey marshmallow center, and a salty-sweet peanut butter topping with crunchy peanuts and rice krispies. They’re easy to make, easy to transport, and keep well in a cooler for warm-weather outings.
Some recipes instantly bring back memories, and for me these salted peanut bars are one of those family favorites. My grandmother would bake a pan for nearly every get-together. Kept in the cooler at outdoor events, they disappeared quickly as cousins and family grabbed them straight from the pan. The combination of textures—a chewy brown sugar base, soft marshmallow middle, and crunchy peanut-topped layer—makes them a picnic favorite.
Why salted peanut bars are ideal for outdoor picnics
These bars travel well and hold up to warm weather better than many desserts because they don’t rely on chocolate that can melt. You can pre-cut the bars at home and transport them in the same pan, using the parchment overhang to lift the entire batch out for easy serving. Keeping them refrigerated or in a cooler until serving ensures the topping stays firm and the marshmallow center remains soft but stable.
How to make the brown sugar crust
The crust is thin, chewy, and flavored with brown sugar. Start by combining flour, brown sugar, baking powder, baking soda, and salt in a medium bowl. Cut or work in softened butter until the mixture resembles coarse crumbs. Add egg yolk and vanilla and mix until combined—the dough will be crumbly; that’s expected. Press the crumbs firmly into a 9 x 9-inch pan lined with parchment paper, using the bottom of a glass or measuring cup to compact the crust evenly.
Bake the crust at 350°F (175°C) for about 12–13 minutes, until it takes on a light golden color. Remove the pan from the oven and immediately add the marshmallows so they’ll begin to soften and puff while still warm.
Tips for preparing the marshmallow and peanut topping
The marshmallow filling is straightforward—just mini marshmallows placed over the hot crust and returned to the oven briefly so they puff up. For the peanut butter layer, follow these tips for an even, spreadable topping:
- Pre-measure ingredients: Measure marshmallows, salted peanuts, and rice krispies before you start so everything is ready to add at the right time.
- Work quickly: Place marshmallows right after the crust comes out of the oven so they puff evenly without browning. When melting the topping (corn syrup, butter, peanut butter chips, and vanilla), combine ingredients until just melted and then immediately stir in peanuts and rice krispies. If you cook or wait too long, the topping becomes too firm to spread.
- Chill before cutting: Let the bars cool in the refrigerator, covered, for at least 45 minutes. Chilling firms the topping and makes neat slicing much easier.
Storage and transport
Use the parchment overhang to lift the bars from the pan, then cut into squares. For transporting, place the bars back into the pan and cover with foil. Keep them refrigerated or in a cooler until serving. Leftovers can be refrigerated (covered) for 4–5 days. To save space, store bars in a single layer in an airtight container or use foil or parchment between layers.
Freezing instructions
These bars freeze well. Place them in an airtight container or a zip-top bag in a single layer, or separate layers with wax paper. Properly wrapped, they’ll keep in the freezer for one to two months. Thaw on the counter for 20–30 minutes before serving so they soften slightly and are easy to bite.
Salted Peanut Bars Recipe
Salty, peanut-buttery, chewy bars with a brown sugar crust and a gooey marshmallow center. Makes about 16 bars.
Ingredients
Crust
- ¾ cup flour
- ⅓ cup packed brown sugar
- ¼ teaspoon baking powder
- ⅛ teaspoon baking soda
- ½ teaspoon salt
- 4 tablespoons unsalted butter, softened
- 1 teaspoon vanilla
- 1 egg yolk
Filling
- 2 cups mini marshmallows
Topping
- ⅓ cup corn syrup
- 2 tablespoons unsalted butter
- 1 teaspoon vanilla
- 1 cup peanut butter chips
- 1 cup salted peanuts
- 1 cup rice krispies
Instructions
Crust and marshmallow layer
- Preheat oven to 350°F (175°C). Line a 9 x 9-inch pan with parchment, leaving an overhang on two sides.
- In a medium bowl, combine flour, brown sugar, baking powder, baking soda, and salt. Cut in softened butter until the mixture is crumbly.
- Stir in egg yolk and vanilla until evenly combined. Press the crumb mixture firmly into the prepared pan using a cup or glass.
- Bake 12–13 minutes, until lightly golden. Immediately distribute mini marshmallows evenly over the hot crust and return to the oven for about 2 minutes, until marshmallows begin to puff. Remove and set aside.
Topping
- In a medium saucepan over medium heat, combine corn syrup, butter, peanut butter chips, and vanilla. Stir until just melted and smooth.
- Remove from heat and quickly stir in salted peanuts and rice krispies, mixing until combined.
- Using two spoons, dollop the peanut topping over the puffed marshmallows and gently spread to cover completely.
- Chill covered in the refrigerator for at least 45 minutes. Once firm, use a sharp knife to cut into squares.
Notes: Store bars refrigerated or in a cooler until serving. They can be frozen up to two months in an airtight container.
For other picnic-friendly desserts: Lemon Crinkle Cookies with White Chocolate; Brown Butter Peach Blondies; Banana Pudding Mason Jars.