Preheat oven to 350 F. Grease a 9x13 pan with cooking spray.
Whisk flour, lemon zest, baking powder, and baking soda together in a bowl. Set aside.
Beat butter and sugar in a large bowl using an electric mixer until light and fluffy.
Beat eggs and egg yolks, one at a time, into creamed butter mixture on low speed, beating well after each addition.
Beat lemon juice into butter mixture.
Add flour mixture, alternating with buttermilk, into the butter mixture just until batter is combined. Pour into 9x13 pan.
Combine flour, sugar and baking powder in a small bowl to make crumbs. Cut butter in until crumbly. Sprinkle evenly over batter.
Bake 35-40 minutes or until a toothpick inserted in center comes out clean. Cool completely in pan on wire rack.