Lemon Cake with Lemon Filling and Lemon Butter Frosting

Instructions:

For the Lemon Cake:

  1. Preheat the oven to 350°F (175°C). Grease and flour two 9-inch round cake pans (or line with parchment paper).
  2. Mix dry ingredients: In a medium bowl, whisk together the flour, baking powder, and salt. Set aside.
  3. Cream butter and sugar: In a large mixing bowl, beat the softened butter and sugar together until light and fluffy, about 4-5 minutes.
  4. Add eggs and flavorings: Add the eggs, one at a time, beating well after each addition. Stir in the lemon zest, lemon juice, and vanilla extract.
  5. Alternate adding dry ingredients and wet ingredients: With the mixer on low speed, gradually add the dry ingredients, alternating with the milk and sour cream (or buttermilk), starting and ending with the dry ingredients. Mix until just combined.
  6. Bake: Divide the batter evenly between the prepared cake pans. Smooth the tops with a spatula. Bake for 28-32 minutes, or until a toothpick inserted in the center comes out clean. Allow the cakes to cool in the pans for 10 minutes before transferring them to a wire rack to cool completely.

For the Lemon Filling:

  1. Combine ingredients: In a saucepan, whisk together the lemon juice, sugar, cornstarch, and water. Bring to a simmer over medium heat, whisking constantly until the mixture thickens, about 2-3 minutes.
  2. Temper the egg yolks: In a separate bowl, lightly beat the egg yolks. Gradually add a small amount of the hot lemon mixture to the yolks, whisking constantly to temper them.
  3. Finish the filling: Pour the egg yolk mixture back into the saucepan with the lemon mixture, whisking continuously. Cook for an additional 1-2 minutes until it becomes thick and glossy. Remove from heat and stir in the butter, salt, and lemon zest.
  4. Cool the filling: Transfer the lemon filling to a bowl, cover with plastic wrap (pressing it directly onto the surface of the filling to prevent a skin from forming), and allow it to cool completely.

For the Lemon Butter Frosting:

  1. Beat the butter: In a large mixing bowl, beat the softened butter until smooth and creamy, about 3-4 minutes.
  2. Add powdered sugar: Gradually add the sifted powdered sugar, 1 cup at a time, mixing on low speed until combined. Scrape down the sides of the bowl as needed.
  3. Add lemon flavor: Once all the powdered sugar is added, mix in the lemon juice, lemon zest, and a pinch of salt. Add heavy cream, one tablespoon at a time, until the frosting reaches your desired consistency (fluffy but spreadable).
  4. Beat until smooth: Continue to beat the frosting for 2-3 minutes until light and creamy.

Assembling the Cake:

  1. Layer the cakes: Once the cakes have completely cooled, place one layer on a cake stand or serving plate.
  2. Add the lemon filling: Spread a generous layer of lemon filling on top of the first cake layer. Be careful not to let it spill over the sides, as the filling can be a bit runny.
  3. Add the second cake layer: Place the second cake layer on top of the lemon filling.
  4. Frost the cake: Using a spatula, apply the lemon butter frosting to the top and sides of the cake. Smooth it out, or create texture with the spatula for a more decorative finish.
  5. Garnish (optional): Garnish with additional lemon zest or thin lemon slices for a fresh touch.