Preheat oven to 350 degrees F.

Spray the inside of a loaf pan with cooking spray and set aside.

Whisk flour, baking powder and salt together in a medium bowl. Set aside.

Combine sugar, butter and lemon zest in a large mixing bowl. Beat for about 2 minutes. Scrape down sides of bowl and add eggs, one at a time, beating after each addition.

Add the lemon juice and vanilla and mix well.

Reduce mixing speed to low and add dry ingredients in 3 additions, alternating with buttermilk in two additions, beginning and ending with dry ingredients.

Pour into prepared pan and bake for 45-50 minutes or until toothpick inserted in the center of the cake comes out clean.

Place the pan on a cooling rack and cool, about 30 minutes.

Carefully invert cake onto rack; remove pan and let cake cool completely.

Dust with powdered sugar if desired.