Ground, freeze-dried corn, aka corn powder, lends an insanely fresh and natural depth, and allows you to make this cake all year round. If blueberries aren't your thing, get creative with a different jammy layer. At Milk Bar, we love the combination of strawberry and corn.
Pro tip: A bent spoon is your friend for applying frostings and spreading fillings with ease. Buy the cheapest spoons you can find from the dollar store and bend it yourself!
Yield: 15-20 servings
CORN SHEET CAKE (makes 2 quarter-sheet pans of cake):
Nonstick cooking spray
2 sticks unsalted butter, softened
4½ cups sugar
4 large eggs
1 cup buttermilk
2/3 cup grapeseed or other neutral oil
1½ cups cake flour
1¼ cups corn powder
1/4 cup plus 1½ tablespoons corn flour
1 tablespoon baking powder
2 teaspoons kosher salt
1. Heat the oven to 350°F. Grease two quarter-sheet pans with nonstick cooking spray and line them with parchment paper, or just line them with silicone baking mats.
2. Combine the butter and sugar in the bowl of a stand mixer fitted with the paddle attachment and cream together on medium-high for 2-3 minutes, until light and fluffy. Scrape down the sides of the bowl halfway through this process, and again at the end of it.
3. Add the eggs, one at a time, beating on medium-high for 1 minute after each addition. After you add the last egg, scrape down the sides of the bowl, then beat on high for 4 more minutes. Scrape down the sides of the bowl again.
4. Combine the buttermilk and oil, and with the mixer on medium speed, stream them into the batter very slowly. It should take you approximately 3 minutes to add these liquids. Scrape down the sides of the bowl, increase the mixer speed to medium-high, and paddle for an additional 2-3 minutes, until the mixture is practically white, twice the size of your original fluffy butter-and-sugar mixture, and completely homogeneous. Don't rush the process. You're basically forcing too much liquid into an already fatty mixture that doesn't want to make room for that liquid. There should be no streaks of fat or liquid. Stop the mixer and scrape down the sides of the bowl.
5. Whisk together the cake flour, corn powder, corn flour, baking powder, and salt in a medium bowl.
6. With the mixer on very low speed, slowly add the dry mixture and mix for 45-60 seconds, just until your batter comes together. Scrape down the sides of the bowl, then mix for an additional 45 seconds to make sure no lumps of flour or powder get left behind.
7. Divide the batter evenly between the quarter-sheet pans and, using a spatula, spread the cake batter into even layers.
8. Bake for 30-35 minutes, rotating the pans front to back halfway through baking. The cakes will rise and puff, doubling in size, but will remain slightly buttery and dense. At 30 minutes, gently poke the edge of each cake with your finger, the cakes should bounce back slightly and the centers should no longer be jiggly. If they don't pass these tests, leave the cakes in the oven for an additional 3-5 minutes.
9. Let the cakes cool in the pans on a wire rack or, in a pinch, in the fridge or freezer. The cooled cakes can be stored in the fridge, wrapped in plastic wrap, for up to 5 days.
JAMMY BLUEBERRY SAUCE (makes about 2 cups):
1½ teaspoons cornstarch
1½ teaspoons water
12 ounces blueberries
1/4 cup sugar
1/8 teaspoon kosher salt
1. In a small bowl, mix together the cornstarch and water to make a slurry.
2. Juice the lemon into a small saucepan and add the slurry, blueberries, sugar and salt. Bring everything to a boil over medium heat.
3. Reduce the heat to low and continue cooking until the blueberries blister and the mixture turns dark blue, 5-6 minutes. The blueberries should still maintain their shape and not break down completely.
4. Cool the sauce before using. The sauce will keep in the refrigerator, in an airtight container, for up to 2 weeks.
CORN CRUMBS (makes about 2 cups):
2/3 cup milk powder
1/2 cup all-purpose flour
2 tablespoons plus 1 teaspoon cornstarch
2 tablespoons corn powder
2 tablespoons plus 2 teaspoons sugar
1 teaspoon kosher salt
6 tablespoons unsalted butter, melted
1. Heat the oven to 250°F. Line a sheet pan with parchment paper or a silicone baking mat.
2. Combine the milk powder, flour, cornstarch, corn powder, sugar and salt in a medium bowl. Toss to mix. Add the melted butter and toss, using a spatula, until the mixture starts to come together and form small clusters.
3. Spread the clusters on the lined sheet pan and bake for 20-25 minutes. The crumbs should be sandy, but still clumped together, just starting to brown around the edges, and your kitchen should smell like buttery heaven. Cool the crumbs completely. The crumbs will keep in an airtight container in the fridge or freezer for up to 1 month.
SOUR CREAM FROSTING (makes about 4 cups):
1 stick plus 7 tablespoons unsalted butter
3¼ cups powdered sugar
1½ teaspoons kosher salt
3/4 cup plus 1 tablespoon sour cream
1 teaspoon freshly squeezed lemon juice
1. Combine the butter, powdered sugar, and salt in the bowl of a stand mixer fitted with the paddle attachment and cream together on medium-high for 6-8 minutes, scraping the bowl down once to make sure there are no butter lumps, until the mixture is smooth and fluffy.
2. Scrape down the sides of the bowl, then, with the mixer on low, stream in the sour cream and lemon juice and continue creaming until the puree is fully emulsified and the frosting is smooth and fluffy again. Increase the speed of the mixer to medium high and mix until the entire mass is bright white, silky, and shiny. It should hold medium soft peaks, like whipped cream.
3. Use the frosting immediately or store it in an airtight container in the fridge for up to 1 week. If you store it in the refrigerator, be sure to loosen it up before using, otherwise it will be impossible to spread. The easiest way to do this is by putting the frosting in the bowl of a stand mixer fitted with the paddle attachment and beating it on medium speed for 3-4 minutes.
1. Put a piece of parchment paper or a silicone baking mat on the counter. Run a knife or offset spatula along the edges of one of the quarter-sheet pans of cake to loosen it from the pan, then invert that cake onto it and peel off the parchment or mat from the bottom of the cake.
2. Clean the quarter-sheet pan and line it anew with clean parchment paper or a silicone baking mat. Place the cake you just unmolded back inside the pan.
3. Dunk a pastry brush in the milk (or use a spoon) and give the cake a good, healthy bath with the milk.
4. Use the back of a spoon to spread half of the sour cream frosting in an even layer over the cake.
5. Sprinkle half of the corn crumbs evenly over the frosting. Use the back of your hand to press them lightly into the frosting, anchoring them in place.
6. Use the back of a spoon to spread the blueberry jam as evenly as possible over the crumbs.
7. Run a knife or offset spatula along the edges of the second quarter-sheet pan of cake to loosen it from the pan, then invert that cake directly on top of the frosting. Peel off the parchment or mat from the bottom of the cake and cover it with the remaining frosting. Give it volume and swirls, or do as we do and opt for a perfectly flat top. Garnish the frosting with the remaining corn crumbs.
8. Transfer the cake to the freezer and freeze for a minimum of 12 hours to set the cake and filling. Once set, if not serving right away, wrap in plastic and freeze for up to 2 weeks.
9. At least 3 hours before you are ready to serve the cake, pull it out of the freezer and, using an offset spatula or a bench scraper, pop the cake out of the pan.
10. Transfer the cake to a cutting board and fill a pitcher with hot water and set it aside. Use a chef's knife to trim the edges of the cake so you are left with flush, smooth sides, submerging the knife in hot water between cuts and wiping the blade clean. This makes for crumb-free, professional looking cuts every time!
11. Place the cake on a large, rectangular platter. Let it defrost in the fridge for a minimum of 3 hours (wrapped well in plastic, the cake can be refrigerated for up to 5 days).
12. Slice the cake into squares and serve.