Preheat oven to 325F. Prepare a bundt pan by spraying generously with non-stick cooking spray or baking spray.
Sift the flour, baking powder, and salt into a medium mixing bowl; set aside.
In a large mixing bowl, cream the butter and sugar together until light and fluffy. Beat in the eggs one at a time, then mix in the sour cream, lemon juice, vanilla extract, and lemon zest. If desired, you can also add 2-3 drops of yellow food coloring for extra yellow color to the cake.
Mix half of the flour mixture into the cake batter, then add the buttermilk. Mix in the second half of the flour mixture just until incorporated (do not over mix).
Pour the cake batter into the prepared bundt pan. Bake at 325F for 60-70 minutes until a toothpick inserted into the center comes out clean. Cool the cake in the pan for 5 minutes, then invert onto a cake plate.