Preheat oven to 375°F. Spray an 8 inch square baking pan with non-stick cooking spray.

In a medium bowl, sift flour, baking powder and salt together.

Using an electric mixer, beat butter, sugar and zest on medium-high speed until light, about 4 minutes. Add eggs, one at a time, beating after each addition. Scrape down bowl as needed.

Alternately add flour mixture and buttermilk. Stir in a third of flour mixture into butter mixture. Add in half of buttermilk mixture. Repeat, ending with flour mixture. Add in vanilla extract and lemon juice. Stir just until fully combined.

Spread batter into pan and sprinkle with blueberries pressing half of the berries down slightly into the cake with the tip of your finger. Bake for about 45-50 minutes or until a toothpick comes out clean.