01 - Preheat oven to 350°F. Grease and flour three 8-inch round cake pans. Line bottoms with parchment paper for easy removal.
02 - In a medium bowl, whisk together flour, baking powder, baking soda, and salt until well combined.
03 - In a large bowl, beat butter and sugar with electric mixer on medium speed until light and fluffy, about 3 minutes.
04 - Add eggs one at a time, beating well after each addition. Mix in lemon zest, lemon juice, and vanilla extract until incorporated.
05 - Alternate adding flour mixture and buttermilk to batter, beginning and ending with flour. Mix just until combined—do not overmix.
06 - Gently fold fresh raspberries into batter using spatula, taking care not to crush berries.
07 - Divide batter evenly among prepared pans and smooth tops. Bake for 25-30 minutes until toothpick inserted in center comes out clean.
08 - Let cakes cool in pans for 10 minutes, then turn out onto wire racks to cool completely before frosting.
09 - Beat butter until creamy. Gradually add powdered sugar, lemon juice, lemon zest, salt, and cream, beating until light and fluffy. Adjust consistency with more cream if needed.
10 - Place one cake layer on serving plate. Spread with frosting. Repeat with remaining layers. Frost top and sides of cake completely.
11 - Garnish with extra raspberries and lemon zest if desired. Chill for 30 minutes before slicing for clean layers.