This post was originally published in August 2019 and has been updated.
Indulge your sweet tooth with these fudgy peanut butter bars. A layer of decadent fudge is sandwiched between layers of rich peanut butter dough... and it all starts with a box of cake mix.
I frequently enjoyed these cake mix fudge-filled peanut butter bars as an after-school treat when I was young. I loved coming home to the peanut butter aroma wafting from the oven.
Since chocolate and peanut butter never go out of style, these bars are still just as scrumptious as I remember.
Why you will love these
- These bars start with a cake mix for ease and convenience.
- Just 6 ingredients stand between you, these bars, and a tall glass of milk.
- Easy to mix together - no electric mixer required.
- Chocolate and peanut butter are always a winning combination.
- Makes a large 9x13 pan (24 bars) - perfect for bake sales, potlucks, or feeding a crowd.
If you love cake mix shortcuts, try:
- Sweetened condensed milk is one of the most wonderful baking ingredients. It adds a deliciously sweet, rich, and creamy consistency.
- Chocolate chips and peanut butter chips - I like using a combination of dark chocolate chips and peanut butter chips. You can substitute milk chocolate or semi-sweet chips for dark chocolate. You can also omit the peanut butter chips and use only chocolate chips. You will need 1 ¾ cups total.
- Peanut butter - I used Skippy creamy peanut butter. If you want to add texture to the bars, try chunky peanut butter. Avoid using reduced-fat peanut butter. The consistency is very different which will affect the consistency of the bars.
Recipe note: The original recipe from my childhood included Coconut Pecan Frosting mix as an optional add-in to the fudge filling. This frosting mix is no longer readily available, so I've omitted it from the recipe and I love the result.
If you wish to add texture to the fudge filling, stir in some shredded coconut and chopped pecans.
Please see the recipe card for complete instructions and ingredient amounts.
- Preheat oven to 350 degrees. Line a 9x13 pan with parchment paper, leaving an overhang on two sides, like a sling.
- In a large mixing bowl, combine cake mix, peanut butter, eggs, and melted butter. (Image 1).
- Stir until fully combined. (Image 2)
- Press ⅔ of the dough into the bottom of the cake pan. Set aside. (Image 3)
- In a small saucepan, combine sweetened condensed milk, chocolate chips, peanut butter chips, and butter. Heat over low until the chips are melted and the mixture is smooth. The mixture will be thick. (Image 4)
- Spread the chocolate mixture in an even layer on top of the dough in the prepared pan. (Image 5)
- Using your fingers, arrange pieces of the remaining dough over the top of the chocolate. (Image 6)
- Bake until set and lightly golden brown. (Image 7)
- Cool completely before slicing.
- Line the baking pan with parchment paper to aid with lifting the cooled bars out of the pan for easy slicing.
- When lining with parchment paper, spray the bottom of the pan with cooking spray first. This will hold the parchment in place while pressing the dough into the pan.
- Chill the bars before slicing. Once the bars have cooled to room temperature, chill them for another 15-20 minutes. This makes it much easier to remove them from the pan and neatly slice them into squares.
- These bars are rich so I like to cut them into 24 squares.
Chocolate morsels or baking chocolate can be used. Chop the baking chocolate to measure 1 cup. Do not use unsweetened baking bars.
No, I do not recommend reduced-fat varieties. The consistency is different and the final result will not be the same.
More chocolate peanut butter treats
Subscribe to My Casual Pantry to get the latest recipes and ideas sent directly to your inbox.
Cake Mix Peanut Butter Fudge Bars
- 1 box (15.25 ounces) yellow cake mix
- 1 cup creamy peanut butter (Note 1)
- ½ cup unsalted butter (melted)
- 2 large eggs
- 1 cup dark chocolate chips (or milk or semi-sweet chocolate)
- ¾ cup peanut butter chips
- 14 ounces sweetened condensed milk
- 2 tablespoons unsalted butter
- Preheat the oven to 350 degrees. Line a 9x13-inch baking dish with parchment paper allowing it to hang over on two sides, like a sling. (Note 2)
- In a large mixing bowl, combine the cake mix, peanut butter, eggs, and ½ cup melted butter. Stir until the dough comes together. Press ⅔ the dough into the prepared pan. (Save the remaining dough to use as the topping.) Set aside.
- In a small saucepan, combine the chocolate and peanut butter chips, sweetened condensed milk, and 2 tablespoons of butter. Melt over low heat, stirring constantly, until melted and combined. Spread this mixture over the dough in the pan. Using your fingers, arrange pieces of the remaining dough over the top of the filling.
- Bake for 20-25 minutes until light golden brown. Cool completely before cutting into squares. Store in an airtight container.
- Do not use reduced-fat peanut butter. The consistency will not be the same.
- Spray the pan with cooking spray before lining it with parchment paper. This will hold the parchment in place, making it easier to spread the dough in the pan.
- After cooling the bars to room temperature, chill them for another 15-20 minutes. This makes it easier to lift them from the pan and neatly slice them.
- Store in an airtight container for up to 5 days.
Nutritional information is an estimate and will vary depending upon the exact amounts and specific ingredients used.