Hot Fudge Sundae Poptart Bar 

Hot Fudge Sundae Poptart Bar Recipe

Ingredients in Hot Fudge Poptarts

*You can find all of the exact quantities and instructions in the recipe card at the bottom of this post. 

Chocolate Cookie Crust

• Salted butter, room temperature – You will find that I always use salted butter in my recipes. If you’re an unsalted butter type of person, you can absolutely sub that in (just be sure to add an extra pinch of salt to the dough). 
• Granulated sugar
• Brown sugar
• Large egg
• Vanilla extract
• All-purpose flour 
• Cocoa powder – I used unprocessed, but Dutch-processed will also work here. 
• Baking soda
• Salt

Vanilla Buttercream Filling

• Salted butter – Again, I’m a fan of salted butter but unsalted works, too. 
• Powdered sugar
• Vanilla

Icing

• Powdered sugar
• Very warm water – Warm water will help bring the icing together and make it spreadable. 
• Light corn syrup – You do not want to skip this! This is what will make the glaze harden like royal icing. If needed, you can use merengue powder (1 tsp) as a replacement. 
• Clear vanilla flavoring – Clear vanilla will keep the icing nice and bright white, rather than a slightly murky white. 
• Cocoa powder
• Sprinkles – I used rainbow sprinkles (fun!) but you can use any colorway you’d like. Which means you could totally make this a Halloween hot fudge sundae poptart bar if you want.

1. Preheat the oven to 350°F (180°C).
2. To make the chocolate crust, cream together the butter and sugars until light in color and fluffy in texture. This will take about 2 minutes. I typically use my stand mixer, but you can also use a hand mixer!
3. Next, add the egg and vanilla extract, mixing until mostly combined.
4. To the mixture, add the flour, cocoa powder, baking soda and salt. Mix until a soft dough forms.
5. Line a 9×13 pan with parchment and press half the dough evenly into the bottom. Lift the parchment with dough out of the pan and freeze. (Alternatively, roll the dough into a 9×13 rectangle on parchment, trim to fit, and freeze.)
6. Grease the 9×13 pan with non-stick spray and then press the remaining half of the dough into the bottom of the pan. The dough will be thin, just work slowly until the bottom of the pan is evenly covered. Set aside.
7. Make the vanilla filling by creaming the butter for 3 minutes, until light in color. Slowly add in the powdered sugar and vanilla extract and mix until combined. The frosting will be thick.
8. Spread the frosting evenly on the cookie dough that has been pressed into the bottom of the pan.
9. Remove the rolled out cookie dough from the freezer. Remove the parchment paper and gently place the second cookie dough sheet on top of the vanilla filling.
10. Use the tines of a fork to gently crimp the edges together and then cut a few venting slits or holes.
11. Bake at 350°F (180°C) for 17-20 minutes or until the edges and center are set and no longer glossy.
12. Remove from the oven and let it cool completely.

Glaze + Decorating Directions

1. Once cool, make the glaze by whisking together the warm water, corn syrup and clear vanilla in a medium sized bowl.
2. Slowly add the powdered sugar to the water mixture, whisking constantly and adding a few drops of warm water as needed until all of the powdered sugar has been incorporated.
3. Once fully mixed, add warm water 1/4 tsp at a time until the glaze reaches a slow dripping consistency.
4. Remove approximately 1 Tbsp of the icing and place it in a small bowl. Whisk the cocoa powder into the small portion of icing and set aside.
5. With the pop tart fully cooled, carefully remove the pop tart from the pan and then pour and spread the white glaze onto the top of the pop-tart.
6. Drizzle the chocolate icing on top of the white icing and then top with sprinkles.
7. Allow the icing to set up completely, cut and enjoy.