Preheat the oven to 350°F. Spray (2) 8 x 4½ x 5-inch metal loaf pans with cooking spray. Set aside.
Sift together the all purpose flour, baking powder, salt and baking soda.
Using a stand or hand mixer, cream together the butter, granulated sugar, and vanilla. Beat until creamy then add the eggs one at a time. Beating well after each addition.
Reserve 1½ Tbsp of lemon zest for the glaze adding the rest to the creamed butter and eggs.
Mix together ¼ cup fresh lemon juice with ¾ cup buttermilk. Add to the mixing bowl alternately with the sifted dry ingredients. Beat until fully combined and all of the dry ingredients are fully moistened.
Divide the batter between the 2 loaf pans. Bounce the pans to release air bubbles.
Bake for 35-40 minutes until a toothpick inserted into the center shows moist crumbs.
Cool in the pan then remove to a cooling rack to cool completely.
To make the glaze, Mix together the powdered sugar, heavy cream, lemon zest and lemon juice until drizzling consistency. If needed add additional cream 1 tsp at a time to thin.
Drizzle the loaf with glaze, sprinkle with ½ Tbsp zest, slice and serve.