Very Lemon Sheet Cake with Silky Sour Cream Frosting
- 2 cups cake flour*
- 2 teaspoons baking powder
- 1/8 teaspoon baking soda
- 8 tablespoons + 6 tablespoon unsalted butter, soft
- 3 tablespoons oil
- 1 1/2 cups Imperial Sugar Extra Fine Granulated Sugar
- 8 large egg yolks at room temperature
- 1 teaspoon salt
- Lemon zest from 4 lemons, no white bitter pith
- 3/4 cup buttermilk, at room temperature
Silky Sour Cream Frosting
- 1 (8 oz) package cream cheese, soft
- 2 cups Imperial Sugar Confectioners Powdered Sugar
- 3/4 cup sour cream
- Zest of 1-2 lemons, no white bitter pith
*Spoon & Sweep method: Use a spoon to fill measuring cup with flour until required amount is obtained. Scooping measuring cup directly into flour bag will firmly pack flour resulting in too much flour required for recipe.
- Preheat oven to 335°F.
- Line a 9x13-inch pan with parchment paper. Alternatively, butter and flour pan and set aside.
- Sift together flour, baking powder, and baking soda, and set aside.
- Mix butter until very creamy and smooth. Add oil and sugar and mix until light and fluffy. Add one egg yolk at a time and mix at least 30 seconds between each.
- Add salt and lemon zest.
- Add 1/3 of flour and mix until combined. Add 1/2 of buttermilk and mix until smooth. Add another 1/3 of flour and mix smooth. Add remaining buttermilk and once combined add remaining flour.
- Scrape batter into pans and place in oven and bake for 33-37 minutes until an inserted toothpick comes clean.
- After 5 minutes turn upside down on a plastic food lined cutting board.
- Once cooled turn upside down onto a serving platter.
- To prepare frosting, mix cream cheese and powdered sugar on lowest speed until completely smooth.
- Add sour cream and lemon zest and combine.
- Frost cake. Serve at room temperature and store airtight.