Preheat your oven to 350 degrees. Prepare a bundt pan by lightly spraying the interior with cooking spray and lightly sprinkling flour over the entire surface. Be sparing with the flour.
In a larger mixing bowl, add the lemon zest, lemon juice, sugar, vegetable oil, and vanilla. Using a handheld mixer, mix all ingredients together.
Add the eggs, one at a time to the lemon juice mixture and beat well after each.
Next, add the buttermilk and beat into the batter. Just beat to incorporate; do not beat long enough to add volume or frothiness to the batter.
Add the flour, baking powder, and baking soda. Beat until the dry ingredients are incorporated into the wet ingredients.
Pour the batter into the prepared bundt pan.
Bake the bundt for 45 minutes. To check for doneness, insert a wooden toothpick into the centre of the cake. If the toothpick comes out clean, the cake is ready. If not, bake for another 2-3 minutes and check again.
Allow the cake to rest in the pan for 10-15 minutes before removing to a wire cooling rack to completely cool. The cake should remain inverted.
When completely cooled, whisk together the confectioner's sugar and lemon juice until smooth. Drizzle over the inverted (bottom) surface of the cake. The icing will harden up in about 10 minutes. Slice and enjoy!