Description
Lemon Bar Sheet Cake with Lemon Curd and Shortbread Crust is a delightful dessert combining a buttery shortbread crust, a zesty lemon cake, and a rich lemon curd topped with creamy lemon buttercream.
Ingredients
Scale
- Shortbread Crust:
- 3 cups shortbread cookie powder (about 11–15 oz cookies pulsed into powder)
- 5 tablespoons unsalted butter, melted
- 1 pinch salt
- Cake:
- Zest of 1 fresh lemon (about 1 tablespoon)
- 3/4 cup buttermilk, room temperature
- 2/3 cup sour cream, room temperature
- 3 whole eggs, room temperature
- 1 egg white, room temperature
- 1 tablespoon vanilla extract
- 1 teaspoon lemon extract (optional)
- 1/3 cup vegetable oil
- 1/4 cup all-purpose flour
- 1 15.25 oz box lemon cake mix
- Lemon Curd:
- 3 egg yolks
- 1 whole egg
- 3/4 cup granulated sugar
- 1/2 cup lemon juice
- Zest of 2 lemons (about 2 tablespoons)
- 4 tablespoons unsalted butter
- Lemon Buttercream:
- 1 1/2 cups unsalted butter, softened
- 1 teaspoon lemon extract
- 1 tablespoon vanilla extract
- 1 pinch salt
- 1/4 cup heavy cream
- 6–7 cups powdered sugar
- 1 drop yellow gel coloring
- Shortbread Crumble (for topping):
- 1 cup shortbread cookies, crumbled
Instructions
- Prep a 9×13 pan with shortening and flour. Preheat oven to 325°F.
- Pulse cookies into a fine powder, measure 3 cups, mix with melted butter and salt.
- Press crust evenly into the pan. No pre-bake needed.
- Whisk together all cake ingredients except the cake mix.
- Sift in the cake mix and gently fold until combined.
- Pour batter over crust and bake 28–30 minutes. Let cool completely.
- In a saucepan over medium heat, whisk together yolks, sugar, juice, and zest until thickened (~6 min).
- Remove from heat, stir in butter until melted. Strain and discard zest.
- Cover with plastic wrap directly on the curd surface and refrigerate until cold.
- Beat butter in a stand mixer until light and fluffy.
- Add salt, lemon extract, vanilla, and heavy cream.
- Gradually add powdered sugar ½ cup at a time, add yellow gel coloring, adjust consistency with more cream if needed.
- Whip on high for 1 minute, then low for 30 seconds to remove air bubbles.
- Spread most buttercream in a flat layer over the cake.
- Pipe 1 1/2 cups buttercream using a 1M tip in long lines.
- Fill gaps with lemon curd.
- Sprinkle shortbread crumble on top.
Notes
- Optional lemon extract enhances the lemon flavor.
- Store cake in an airtight container in the fridge for up to 3–4 days.
- The extra curd can be used on the side or for additional decoration.
- Prep Time: 30 minutes
- Cook Time: 30 minutes
- Category: Dessert
- Method: Baking
- Cuisine: American
Nutrition
- Serving Size: 1 piece
- Calories: 350
- Sugar: 25g
- Sodium: 150mg
- Fat: 18g
- Saturated Fat: 10g
- Unsaturated Fat: 8g
- Trans Fat: 0g
- Carbohydrates: 45g
- Fiber: 1g
- Protein: 4g
- Cholesterol: 70mg
Keywords: Lemon Bar Sheet Cake, Lemon Curd, Shortbread Crust, Dessert Recipe