01 - Preheat your oven to 350°F. Thoroughly grease and flour a 9-inch round cake pan, or line it with parchment paper for easier release.
02 - In a medium mixing bowl, whisk together the all-purpose flour, baking powder, baking soda, and salt until well combined. Set this dry mixture aside.
03 - In a large mixing bowl, cream the softened unsalted butter and granulated sugar together using an electric mixer or whisk. Continue mixing for 2 to 3 minutes until the mixture is light and fluffy.
04 - Beat in the large eggs one at a time, ensuring each egg is fully incorporated into the mixture before adding the next.
05 - Stir in the lemon zest, fresh lemon juice, and vanilla extract. Mix until these bright flavors are just combined.
06 - In a separate small bowl, whisk together the whole milk and sour cream (or plain Greek yogurt) until smooth.
07 - Gradually add the reserved dry ingredients to the wet mixture in three parts, alternating with the milk and sour cream mixture. Begin and end with the dry ingredients. Mix gently until just combined; be careful not to overmix the batter.
08 - In a small bowl, lightly toss the fresh blueberries with 1 tablespoon of flour. This coating helps prevent the berries from sinking to the bottom of the cake. Gently fold the floured blueberries into the cake batter.
09 - Pour the prepared batter evenly into the greased and floured cake pan. Smooth the top with a spatula. Bake for 35 to 40 minutes, or until a wooden skewer or toothpick inserted into the center of the cake comes out clean.
10 - Allow the baked cake to cool in its pan for 10 minutes. Afterward, carefully transfer it to a wire rack to cool completely before proceeding.
11 - Once the cake is fully cooled, prepare the glaze. In a small bowl, whisk together the powdered sugar with 2 to 3 tablespoons of fresh lemon juice until the mixture is smooth and has a pourable consistency.
12 - Drizzle the prepared lemon glaze evenly over the cooled cake. Allow the glaze to set for approximately 15 minutes before slicing and serving this delightful dessert.