Step 1

Preheat the oven to 350 degrees Fahrenheit (175°C). Grease a 9x13-inch baking pan with butter or cooking spray, line it with parchment paper, and set aside.

Step 2

In a large bowl, whisk the flour, baking powder, baking soda, and salt until well blended.

Step 3

In a separate large bowl, beat the sugar and butter with an electric mixer until light and fluffy - about 5 minutes. Add the eggs one at a time, beating well after each addition until smooth. Finally, add the lemon zest, lemon juice, and vanilla, and stir to combine.

Step 4

Alternate adding the dry ingredients and sour cream, starting and ending with the flour. Stir by hand with a spatula until just combined and no streaks of flour are visible.

Step 5

Pour the batter into the prepared pan, smooth the top with a spatula, and bake for 30-35 minutes or until a toothpick inserted in the middle comes out clean. Remove from the oven and let cool on a wire rack.

Step 6

While the cake is cooling, add 3 cups of powdered sugar to a large bowl. Slowly whisk in the lemon juice until smooth and lump-free. Add more powdered sugar, as needed.

Step 7

Pour the glaze over the cooled cake and spread evenly over the surface. Garnish with lemon zest, if desired, and chill for 20-30 minutes or until the glaze is set. Then slice, serve, and enjoy!