Tangy Lemon Bar Sheet Cake with Shortbread Crust - Recipe By Me

Ingredients

• 3 cups shortbread cookie powder (11-15oz pulsed into a powder)
• 5 tablespoons unsalted butter, melted
• 1 pinch salt
• 1 tablespoon fresh lemon zest (about 1 lemon)
• 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 box (15.25oz) lemon cake mix (Duncan Hines preferred)
• 3 egg yolks
• 1 whole egg
• 3/4 cup granulated sugar
• 1/2 cup lemon juice
• 2 tablespoons lemon zest (about 2 lemons)
• 4 tablespoons unsalted butter
• 1 1/2 cups unsalted butter, slightly softened
• 1 teaspoon lemon extract
• 1/4 cup heavy cream
• 6-7 cups powdered sugar
• 1 drop yellow gel food coloring
• 1 cup shortbread cookies, crumbled