Step 1: Make the Strawberry Reduction

1. In a saucepan over medium heat, combine strawberries, sugar, and lemon juice.
2. Simmer for 15-20 minutes, stirring occasionally, until thickened.
3. Blend into a puree, then let cool completely before using.

Step 2: Make the Cake Batter

1. Preheat oven to 350°F (175°C). Grease and line two 9-inch cake pans with parchment paper.
2. In a bowl, whisk together flour, baking powder, baking soda, and salt.
3. In another large bowl, beat butter and sugar until light and fluffy (about 2-3 minutes).
4. Add eggs one at a time, mixing well after each. Stir in vanilla extract.
5. Alternate adding the dry ingredients and buttermilk, starting and ending with the dry ingredients.
6. Gently fold in ½ cup strawberry reduction.

Step 3: Bake the Cake

1. Divide batter evenly between the prepared cake pans.
2. Bake for 25-30 minutes, or until a toothpick inserted in the center comes out clean.
3. Let cakes cool in the pans for 10 minutes, then transfer to a wire rack to cool completely.

Step 4: Make the Strawberry Buttercream

1. In a large bowl, beat butter until creamy.
2. Gradually add powdered sugar, mixing well.
3. Add strawberry reduction and vanilla extract, beating until fluffy.
4. If needed, add 1-2 tablespoons heavy cream for a smooth consistency.

Step 5: Assemble the Cake

1. Place one cake layer on a serving plate and spread strawberry buttercream on top.
2. Add the second cake layer and frost the entire cake with the remaining buttercream.
3. Decorate with fresh strawberries and serve!