Cake Ingredients

• 1 cup (2 sticks) unsalted butter, room temp
• ½ cup neutral oil (like canola or vegetable — for moisture)
• 2 ¾ cups granulated sugar
• 5 large eggs + 2 egg whites, room temp
• 3 ½ cups cake flour, sifted
• 1 tbsp baking powder
• ½ tsp salt
• ¾ cup whole milk, room temp
• ¾ cup sour cream, room temp
• 1 tbsp vanilla extract
• 1 to 1 ½ tsp lemon extract (adjust to your liking)
• Zest of 1 lemon (optional)

Cake Instructions

1. Preheat oven to 325°F. Grease and line three 9-inch round pans with parchment.
2. Cream butter, oil & sugar together until light and fluffy (4–5 minutes).
3. Add eggs and egg whites one at a time, mixing well after each.
4. In a separate bowl, sift together cake flour, baking powder, and salt.
5. In another bowl, whisk together milk, sour cream, vanilla, and lemon extract.
6. Alternate adding dry and wet ingredients to the batter in 3 additions, starting and ending with dry.
7. Mix in lemon zest, if using, and beat just until combined and smooth.
8. Divide evenly between the 3 pans, smooth the tops.
9. Bake 35–45 minutes, or until toothpick comes out with just a few crumbs.
10. Cool in pans 10 minutes, then turn out to racks and cool completely.

Buttercream Frosting Ingredients

• 1 ½ cups (3 sticks) unsalted butter, room temp
• 5–6 cups powdered sugar, sifted (start with 5 cups)
• 4–6 tbsp heavy cream (or whole milk)
• 1 tbsp vanilla extract
• ¼ tsp lemon extract (or less, to taste)
• Pinch of salt

Frosting Instructions

1. Whip the butter on medium-high speed for 3–5 minutes until pale and super fluffy.
2. Add 5 cups powdered sugar 1 cup at a time, mixing on low at first, then medium.
3. Add vanilla, lemon extract, and a pinch of salt.
4. Drizzle in cream, 1 tablespoon at a time, until the texture is soft and spreadable but holds shape.
5. Once combined, whip on high for 2–3 minutes to lighten it even more.

Assembly of cake

• Stack and frost the cake layers on a greaseproof cake board or flat plate.
• Spread an even layer of buttercream on top of each cake layer as you stack them with a large offset spatula.
• Repeat with the remaining cake layers, then freeze the cake for about 10 minutes to firm up the buttercream and reduce crumbling, making it easier to frost.
• Cover the cake with an even layer of buttercream, smoothing it with a large spatula.