Quarter Sheet Cakes Recipe

Prepare and preheat

Position an oven rack in the center of the oven and preheat to 350°F (175°C). Lightly grease a quarter-sheet pan (9 x 13-inch) with nonstick spray or butter and line the bottom with parchment, leaving an overhang for easy removal.

Combine dry ingredients

In a large bowl, whisk together the all-purpose flour, baking powder, baking soda, and salt until evenly distributed.

Cream butter and sugar

In a stand mixer fitted with the paddle (or in a large bowl with a hand mixer), beat the softened butter and granulated sugar on medium-high speed for 3–4 minutes until light and fluffy and pale in color.

Add eggs and vanilla

Reduce mixer speed to medium and add eggs one at a time, beating briefly after each addition to incorporate. Scrape down the bowl as needed. Add the vanilla extract and mix until combined.

Alternate dry and wet

With the mixer on low, add the flour mixture in three parts, alternating with the milk and buttermilk (add flour, then half the milks, flour, remaining milks, then final flour). Mix just until combined after each addition; do not overmix.

Adjust batter consistency

If batter seems too thick, add up to 2 tablespoons additional milk to reach a spreadable but not runny consistency suitable for a quarter-sheet pan.

Pour and bake

Spread the batter evenly in the prepared quarter-sheet pan, smoothing the top with an offset spatula. Bake in the preheated 350°F (175°C) oven for 22–28 minutes, or until the top is golden and a toothpick inserted in the center comes out with a few moist crumbs.

Cool

Allow the cake to cool in the pan on a wire rack for 15 minutes. Run a knife around the edges, then lift the cake out using the parchment overhang and transfer to the rack to cool completely before frosting (about 1 hour).

If making a chocolate version, whisk the unsweetened cocoa powder into the dry ingredients in the 'Combine dry ingredients' step. Replace the cup of hot water or coffee for the milk/buttermilk combination: dissolve the cocoa into the hot coffee, let cool slightly, then add the coffee in place of the milk + buttermilk when alternating wet and dry. Reduce total flour by 2–4 tablespoons if batter seems too thick.

Beat butter

Ensure butter is softened. In a large bowl or stand mixer fitted with the paddle, beat the softened butter on medium speed for 1–2 minutes until smooth and slightly pale.

Add sugar and salt

With the mixer on low, gradually add the confectioners' sugar, about 1 cup at a time, mixing to incorporate and preventing a sugar cloud. Add the salt and vanilla.

Adjust texture

Once the sugar is incorporated, add the heavy cream (or milk) 1 tablespoon at a time and increase mixer speed to medium-high. Beat the frosting 2–3 minutes until light, fluffy, and spreadable. Add more cream if too stiff, or more powdered sugar if too thin, to reach a consistency ideal for spreading on a sheet cake.

Tint or flavor (optional)

If desired, divide and tint with gel food coloring or fold in additional flavorings (cocoa for chocolate buttercream, citrus zest, etc.).

Frost cake

Once the cake is completely cool, place it on a serving tray. Using an offset spatula, spread an even layer of buttercream over the top. For a clean edge, use a bench scraper and chilled spatula. Decorate with piped borders, sprinkles, or dusting of powdered sugar/cocoa as desired.

Slice and serve. For neat squares, refrigerate the frosted cake for 20–30 minutes to firm the buttercream, then use a sharp knife wiped between cuts to slice into portions. Store leftover cake covered at room temperature for up to 2 days, or refrigerate up to 5 days (bring to room temperature before serving).