Prep time: 40 minutes
Cook Time: 35-40 minutes
Total time: 1 hour and 20 minutes (plus cooling time)
Yield: 12 serrvings
For the cake
2 cups all-purpose flour
1/2 teaspoon salt
1 teaspoon baking soda
1 cup (2 sticks) unsalted butter, softened
1/3 cup Smooth Operator peanut butter
2 cups granulated sugar
2 eggs, lightly beaten
1 teaspoon vanilla extract
12 ounces buttermilk
For the soaking liquid
8 ounces strawberries, greens removed, cut into pieces
1/4 cup granulated sugar
1 package (3 ounces) strawberry gelatin dessert (not instant)
3/4 cup boiling water
1/2 cup cold water
For the frosting
2 sticks unsalted butter, softened
1/4 cup Smooth Operator Peanut Butter
6-8 cups confectioners’ sugar
1 teaspoon vanilla extract
Blue food coloring (optional)
Sliced strawberries, for garnishing slices
1. Generously grease the bottom and sides of a 9×13-inch baking pan. If desired, line the bottom of the pan with parchment paper. In a large bowl, sift together the flour, salt, and baking soda. Set to the side.
2. In the bowl of a stand mixer fitted with the paddle or rotary attachment, cream the butter and peanut butter until creamy and mixed, about 2 minutes on high speed. Add the sugar, and continue mixing until the mixture is light and fluffy, about 2 more minutes on high speed. Pause the mixer and scrape down the sides of the bowl with a rubber spatula as needed.
3. Pause the mixer, and add the eggs, one at a time, mixing on low speed after each addition and scraping the sides of the bowl as needed. Stir in the vanilla.
4. Add the flour mixture and the buttermilk in 2-3 additions each, beginning and ending with the flour. Do not overmix.
5. Spread the fairly thick batter into your prepared pan. Bake for 35-40 minutes, rotating the pan at the 20-minute mark.
6. Remove the cake from the oven, and let it cool for several minutes. While it cools, prepare the filling.
7. Combine the strawberries and sugar in a medium saucepan. Cook over low heat, stirring frequently, until the strawberries begin to release juice. You can gently mash the berries to get more liquid out of them. Once the berries feel completely softened and cooked, remove from heat. Strain the liquid, reserving the berries.
8. Place the gelatin powder in a heatproof bowl. Add the boiling water and the strawberry liquid, and mix until the gelatin is totally dissolved. Stir in the cold water, and whisk until the gelatin begins to slightly thicken.
9. Poke the surface of the cake all over with a skewer, at 1/2 inch intervals.
10. Pour the slightly thickened but still pourable gelatin mixture over the cake, evenly pouring it on top. Let the cake cool to room temperature before frosting.
11. To make frosting, cream the butter and Smooth Operator peanut butter until smooth and creamy. Add 3 cups of the confectioners’ sugar, and mix on low until incorporated. Stir in the vanilla. Add the remaining sugar, one cup at a time, until you have reached your desired spreading consistency. If desired, tint the frosting blue with blue food coloring.
12. Spread the frosting on top of the cooled cake (still in the baking pan). Slice into 12 rectangles, and top individual slices with either fresh strawberry slices or the reserved cooked berries from step 7.
13. Store leftovers, well wrapped, in the refrigerator for up to 2 days. Let the cake come to room temperature before serving.