Peanut Butter Cup Stuffed Blondies with Peanut Butter Frosting & Chocolate Ganache

A close-up on a peanut butter blondie, frosted in peanut butter frosting and chocolate ganache.

5 from 4 votes

Peanut Butter Cup Stuffed Blondies with Peanut Butter Frosting & Chocolate Ganache

Peanut Butter Blondies are the ultimate peanut butter lover's treat! These fudgy blondies are stuffed with peanut butter cups, topped with a luxurious peanut butter frosting, and finished with a silky chocolate ganache. They taste like a giant, fancy peanut butter cup in bar form!

Prep Time35

Cook Time28

Total Time1 3

Course: Dessert, Dessert Bars

Cuisine: American

Keyword: Blondies, Peanut Butter Dessert

Servings: to 32 bars

Author: Stephanie Simmons

Ingredients

For the Blondies

1 cup salted butter, melted 226 grams
2 cups + 3 tbsp dark brown sugar, packed 465 grams
2 tsp vanilla extract 8 grams
3 large eggs, at room temperature
1 large egg yolk, at room temperature
2 and 1/3 cups all-purpose flour, spooned & leveled or weighed out 303 grams
1/8 tsp salt
1 and 1/4 tsp baking powder
22 large peanut butter cups, divided See Note below!!

Peanut Butter Frosting

1/4 cup salted butter, softened at room temperature 56 grams
1 cup creamy peanut butter 280 grams
1 cup powdered sugar (plus 1-2 tbsp, to taste) 115 grams
1/4 cup heavy cream 60 grams
1 tsp vanilla extract 4 grams
pinch of salt

Chocolate Ganache

8 ounces semi-sweet chocolate, finely chopped Use good-quality baking bars here, like Ghirardelli, Baker's, Lindt, etc. - 226 grams
1 cup heavy cream 240 grams

For Topping

handful of chopped peanuts
a few extra peanut butter cups, chopped
sprinkle of flaky sea salt

US Customary - Metric

Instructions

Prep: Preheat your oven to 350℉. Spray a 9x13 metal (see note) baking dish with nonstick spray and line with parchment paper. Chop 10 peanut butter shapes (like Reese's eggs), or 16-18 small peanut butter cups (like the Reese's foil wrapped size).
Make the Blondies: Melt butter in a large mixing bowl. Whisk in brown sugar until well combined. Whisk in the vanilla, eggs, and egg yolk until smooth and thick. Add the flour, salt, and baking powder and gently fold in until a few streaks of flour remain, then add the chopped peanut butter cups and stir to distribute. Spread half the batter into your prepared baking dish. Lay down whole peanut butter cups/shapes in 4 rows of 3 each. Cover with the remaining batter.
1 cup salted butter, melted, 2 cups + 3 tbsp dark brown sugar, packed, 2 tsp vanilla extract , 3 large eggs, at room temperature , 1 large egg yolk, at room temperature , 2 and 1/3 cups all-purpose flour, spooned & leveled or weighed out , 1/8 tsp salt, 1 and 1/4 tsp baking powder, 22 large peanut butter cups, divided
Bake: Bake the bars for 27 to 30 minutes. The top will have a golden, almost crinkly/shiny crust, and a toothpick inserted into the center will pull out some thick blondie filling. The center will appear set. Place pan on a wire rack to cool until you are able to lift the bars out, then let cool completely on the wire rack without the pan.
Make Peanut Butter Frosting: In a medium bowl, beat together butter and peanut butter until creamy. Add the powdered sugar, then mix in the heavy cream, vanilla, and salt. Taste and add 1-2 tbsp of powdered sugar if desired. Spread evenly over the cooled blondies. Pop in the fridge to let the frosting chill while you make the ganache.
1/4 cup salted butter, softened at room temperature , 1 cup creamy peanut butter, 1 cup powdered sugar (plus 1-2 tbsp, to taste), 1/4 cup heavy cream, 1 tsp vanilla extract , pinch of salt
Make Ganache: Add finely chopped chocolate to a small bowl. Heat heavy cream in a small saucepan over medium heat until simmering. Pour over the chocolate, let sit for 4 minutes, then stir until completely smooth. If any lumps remain, microwave for 5-8 second bursts as needed, stirring between, until completely smooth.
Let the ganache cool in the fridge for 10-15 minutes, so it's a bit thicker and doesn't run down the sides of your bars. Pour the ganache over the bars, and use the back of a spoon to make some swirls. Sprinkle on extra toppings if desired - chopped peanuts, chopped peanut butter cups, and a little flaky sea salt.
Chill in the fridge until the ganache is completely set, about 1 hour.
8 ounces semi-sweet chocolate, finely chopped, 1 cup heavy cream
Serve & Store: Slice into bars and enjoy! Store leftovers in an airtight container in the fridge for 3-4 days.
Tip: For clean slices, wipe the knife between each slice.
handful of chopped peanuts, a few extra peanut butter cups, chopped, sprinkle of flaky sea salt
Make-Ahead Tip: Bars can be made 1 day ahead and stored in an airtight container or covered with foil in the cooled baking pan at room temperature.
Frosting can be made 1-2 days ahead and refrigerated in the covered mixing bowl. Let sit at room temperature for 10-15 minutes then beat with a mixer to get it back to spreadable consistency before using.
Make the ganache fresh the day of.

Notes

Peanut Butter Cups: This is a dessert I always make for Easter, so I am usually using the Reese's pb eggs. These are a bit larger than the mini Reese's cups (the foil wrapped kind), so you'll need maybe 6-8 additional for chopping and adding into the batter if using these instead of a holiday shape size.

Metal 9x13 Pan: Metal conducts heat much better and more evenly than ceramic or glass, so it's my first preference for baking. Ceramic is an ok substitute, but stay away from glass - it just doesn't bake things evenly because glass conducts heat poorly.

Nutrition