This Butterscotch Krimpet Sheet Cake recipe is a spin on the classic butterscotch krimpets from Tastykakes. Made in a 13" x 9" pan, this classic Pennsylvania favorite combines a vanilla sponge cake base with a thick layer of creamy butterscotch frosting on top. If you grew up loving this classic treat, you will absolutely love this version!
Adjust your oven rack to the 2nd level mark and preheat your oven to 350ºF.
Generously spray a 13" x 9" cake pan with a flour-based baking spray, lay a sheet of parchment paper across length-wise, then re-spray the top of the parchment paper.
In a medium-size mixing bowl, whisk together the all-purpose flour, baking powder, and salt. Set to the side.
2 cups All-Purpose Flour, 1 ½ teaspoon Baking Powder, ¼ teaspoon Salt
Using a hand-held mixer or a stand mixer fitted with the whisk attachment, whisk the eggs on medium-high speed until they are thick and frothy in appearance.
4 large Eggs
Add in the vegetable oil, granulated sugar, light brown sugar, vanilla extract, and milk.
¼ cup Vegetable Oil, 1 cup Granulated Sugar, ½ cup Light Brown Sugar, 2 teaspoon Vanilla Extract, 1 cup Whole Milk
Reduce the mixer speed to low, then gradually add in the whisked dry mixture until just combined. Scrape down the sides of the bowl if needed, then give it one more whisking. Be careful not to over mix the cake batter. The cake batter will be on the runny, thinner side.
Pour the cake batter into the prepared 13" x 9" cake pan, then bake at 350ºF for 25-30 minutes until an inserted toothpick into the center of the cake comes out clean. For reference, my cake took 30 minutes to bake.
Cool the sheet cake in the pan for 10-15 minutes. Then, using the parchment paper sling, remove the cake from the pan and place on a wire cooling rack to cool completely.
You can frost the sheet cake with the butterscotch frosting once it has cooled using an offset spatula.
butterscotch frosting
In a small microwaveable bowl, melt the butterscotch chips in 30-45 second increments at 50% power, stirring between, until fully melted and smooth. Set to the side to cool slightly.
⅔ cup Butterscotch Chips
Using a hand mixer or a stand mixer fitted with the paddle attachment, beat the unsalted butter until smooth and creamy. Add in the melted butterscotch and mix until full incorporated.
1 cup Unsalted Butter
Reduce the mixer speed to low and gradually add in the sifted powdered sugar, heavy whipping cream, and salt. Scrape down the sides of the bowl as needed.
4 cups Powdered Sugar, 3-4 tablespoon Heavy Whipping Cream, ¼ teaspoon Salt
Notes
sheet cake notes
The recommended baking time for this butterscotch krimpet sheet cake recipe is 350ºF for 25-30 minutes. Because ovens bake differently, I suggest checking your cake at the earliest recommended bake time first.
While very helpful with removing the sheet cake for cooling and frosting, the parchment paper sling step is optional.
After pouring the cake batter into the pan, I always like to give it a few light taps to remove any air bubbles.
I didn't try this, but you can bake this in a 10" x 15" x 1" jelly roll pan. You'll need to adjust your baking times.
I cut this butterscotch krimpet sheet cake into 15, albeit unevenly sized squares, but you can cut them smaller or bigger if preferred. You can also get fancy and cut them into the waves like the Tasty Kakes brand does.
butterscotch frosting notes
If you find that the frosting is too thick and unspreadable, you can add in a little bit of heavy cream. Likewise, if you find it to be too thin, add in a little more confectioners sugar to thicken it.
This butterscotch frosting recipe will make enough for a thick layer of frosting across the top of your sheet cake. If you'd prefer to have a thinner layer, like what you'd see with the store-bought version, you can half the recipe.