Preheat the oven to 350℉. Prepare a 10-cup bundt pan by greasing with melted butter and flour.
In a large mixing bowl, whisk flour, baking powder, and baking soda to combine. Set aside.
In a medium mixing bowl, use a stand mixer or electric hand mixer to beat sugar and butter on medium-high speed until pale and creamy. This should take 2-4 minutes. Add the eggs, one at a time, beating on medium speed to combine. Add the sour cream, milk, lemon extract and lemon zest. Mix again to combine.
Add bowl of wet ingredients to the bowl with flour mixture, and stir until just combined. *Ensure there are no visible streaks or clumps of flour, but avoid over mixing the cake batter.
Pour the batter into the prepared bundt pan.
Bake in preheated oven for 45-50 minutes, or until a toothpick inserted into the cake is dry or has a few moist crumbs when removed.
Allow the cake to cool in a pan on a wire rack for 1 hour before removing. Place the cake on a serving platter. When the bundt cake is cool, make the glaze.
To a small bowl, add powdered sugar, lemon juice, lemon zest, and melted butter. Stir well to combine. If the glaze seems too thick, stir in milk, water, or lemon juice, 1-2 teaspoons at a time, until consistency is to your liking. To thicken the cake glaze, stir in more powdered sugar, 1 tablespoon at a time.
Drizzle glaze over the cool cake, then slice and serve.
Notes
For the best results, bring all of your ingredients to room temperature before you start making this recipe.
Storage - Keep the dessert an airtight container in a cool, dry place. You can also freeze the cake for up to three months. I would remove any lemon slices used as garnish before doing so.
Garnish ideas: To elevate the appearance, you can sprinkle the dessert with a dusting of powdered sugar, lemon zest, whipped cream, slices of lemon, etc.