In a medium bowl, whisk together flour, cornstarch, baking powder, baking soda, and salt. Set aside.
2 ¾ cups all-purpose flour, 1 tablespoon cornstarch, 2 teaspoons baking powder, 1/4 teaspoon baking soda, 1/2 teaspoon fine salt
In a large mixing bowl add the sugar and lemon zest and rub everything together with your fingers to release the lemon oils.
2 cups granulated sugar, Zest of 3-4 large lemons
Add in the softened butter to the sugar and beat on medium-high speed for 3-4 minutes until light and fluffy.
1 cup unsalted butter, softened
Add eggs one at a time, mixing well after each addition.
4 large eggs
Mix in the vanilla extract, lemon juice, sour cream, and oil until fully combined.
2 teaspoons vanilla extract, ¼ cup fresh lemon juice, ½ cup sour cream, room temperature, 1/3 cup neutral oil (vegetable or canola)
Gradually add the dry ingredients in two additions, alternating with the milk. Start and end with the flour mixture. Mix until just combined, don’t overmix!
1/4 cup whole milk or buttermilk, room temperature
Generously grease and flour a 10-12 cup bundt pan or Baker's Joy non stick spray if you want something easier. You can also use melted shortening just make sure to get it in every crack and crevice, then dust with flour to cover every area of the pan.
Pour the batter into the prepared bundt pan and smooth the top.
Bake for 48-50 minutes, or until a skewer inserted in the center comes out clean with a few moist crumbs.
Soak in Lemon Syrup (for Extra Moisture!)
While the cake bakes, heat 1/3 cup lemon juice + 1/3 cup sugar in a saucepan over low heat until the sugar dissolves.
1/3 cup fresh lemon juice, 1/3 cup granulated sugar
Once the cake is out of the oven, poke holes in the top with a skewer or toothpick and brush the warm syrup all over the cake while it’s still hot.
Let the cake cool in the pan for 15 minutes, then invert onto a wire rack to cool completely.
Make the Thick Lemony Glaze
Whisk together powdered sugar, lemon juice, and heavy cream until smooth and thick enough to coat the cake generously.
2 cups powdered sugar, 2 tablespoons fresh lemon juice, 1-2 tablespoon milk or heavy cream
Pour over the cooled bundt cake, letting it drip down the sides. Top with more lemon zest if you'd like