Lemon Poppyseed Sheet Cake

By Sam Pierce

Ingredients

For the Cake

  • 1 1/2 cups all-purpose flour
  • 2 tablespoons cornstarch
  • 2 teaspoons baking powder
  • 1 1/2 tablespoons poppy seeds
  • 1/4 teaspoon salt
  • 1/2 cup + 1 tablespoon unsalted butter, softened
  • 3 tablespoons vegetable oil
  • 1 cup + 2 tablespoons granulated sugar
  • 2 tablespoons lemon zest (from ~1 large lemon)
  • 3 large eggs, room temperature
  • 1/4 cup milk, room temperature
  • 1/4 cup + 2 tablespoons sour cream
  • 3 tablespoons fresh lemon juice

For the Cream Cheese Frosting

  • 6 tablespoons unsalted butter, softened
  • 6 oz cream cheese, softened
  • 2 1/4 cups powdered sugar
  • 2-3 tablespoons milk
  • Lemon curd, for topping (optional)

Mixing the Cake Batter

To begin, preheat your oven to 350°F. Use cooking oil or cooking spray to coat an 8×8 inch baking dish. Place a piece of parchment paper into it to line the bottom.

In a medium-sized bowl, sift together the following ingredients: all-purpose flour, cornstarch, baking powder, poppy seeds, and salt. Then, whisk them together to combine. Next, set this mixture aside.

Next, place the granulated sugar and lemon zest into a large mixing bowl; using your fingers combine (rub) the lemon zest with the granulated sugar, until you can smell the lemon zest; this will help intensify the flavour of the cake.

Add the softened butter and vegetable oil into the sugar/lemon mixture and mix them together using an electric stand mixer or hand mixer at medium speed for 2-3 minutes, until the mixture is light and fluffy.

Add the eggs to the mixture, one egg at a time, mixing between each addition.

Next, add the milk, sour cream, and lemon juice to the combined mixture and mix until the ingredients are just combined (at this point the cake batter may look a bit curdled; this is OK).

Finally, take the combined wet ingredients and add them to the combined dry ingredients; gently fold the wet ingredients into the dry ingredients using a spatula only until all of the dry ingredients have been incorporated (be cautious not to over-mix as this will yield a tough cake).

Baking the Cake

Pour the prepared cake batter into the greased baking dish, then spread it into an even layer in the baking dish.

Bake the cake in the preheated oven for approximately 25-30 minutes, or until you can insert a toothpick into the centre of the cake and it comes out clean (with or without a few moist crumbs attached).

Once the cake is completely cool, you may frost it.

Making the Frosting

To create the frosting, first place the softened butter and cream cheese into a large mixing bowl and mix until light and fluffy.

Afterward, gradually add the powdered sugar in three additions to the creamed mixture, mixing well between each addition; once finished, continue adding (one tablespoon at a time) milk until the frosting is smooth and spreadable.

Finally, frost the cooled cake evenly with frosting.

To finish your cake, using a knife or a spoon, make small dollops of lemon curd on top of the frosting and swirl it into the frosting using a large spoon.

Lemon Poppyseed Sheet Cake

This is a moist, zesty lemon poppyseed cake with a cream cheese frosting. It’s a straightforward recipe that doesn’t require complex techniques. The cake batter comes together quickly, and the finished cake has a tender crumb and is topped with a tangy frosting, with an option to swirl in lemon curd.
Print Pin Rate
Prep Time: 25 minutes
Cook Time: 30 minutes
Cooling Time: 1 hour
Total Time: 1 hour 55 minutes

Ingredients

For the Cake

  • 1 1/2 cups all-purpose flour
  • 2 tablespoons cornstarch
  • 2 teaspoons baking powder
  • 1 1/2 tablespoons poppy seeds
  • 1/4 teaspoon salt
  • 1/2 cup + 1 tablespoon unsalted butter softened
  • 3 tablespoons vegetable oil
  • 1 cup + 2 tablespoons granulated sugar
  • 2 tablespoons lemon zest from ~1 large lemon
  • 3 large eggs room temperature
  • 1/4 cup milk room temperature
  • 1/4 cup + 2 tablespoons sour cream
  • 3 tablespoons fresh lemon juice

For the Cream Cheese Frosting

  • 6 tablespoons unsalted butter softened
  • 6 oz cream cheese softened
  • 2 1/4 cups powdered sugar
  • 2-3 tablespoons milk
  • Lemon curd optional, for topping

Instructions

  • Preheat oven to 350°F. Grease 8×8 inch pan and line bottom with parchment.
  • Sift together flour, cornstarch, baking powder, poppy seeds, and salt.
  • Rub lemon zest into sugar until fragrant.
  • Beat butter, oil, and lemon-sugar mixture until light and fluffy, 2-3 minutes.
  • Beat in eggs one at a time.
  • Mix in milk, sour cream, and lemon juice until just combined.
  • Fold dry ingredients into wet ingredients until just combined.
  • Pour batter into pan and bake 25-30 minutes until toothpick comes out clean.
  • Cool completely in pan.
  • Beat butter and cream cheese until light and creamy.
  • Gradually mix in powdered sugar, adding milk until spreadable.
  • Spread frosting over cooled cake.
  • Optional: Swirl lemon curd into frosting.

Notes

Do not overmix batter. Slight curdling when adding wet ingredients is normal.
Tried this recipe?Leave a comment below & let me know!