01 - Preheat oven to 350°F. Grease and flour a 9-inch round cake pan or line with parchment paper for non-stick release.
02 - In a medium bowl, thoroughly whisk together the all-purpose flour, baking powder, baking soda, and salt. Reserve this mixture.
03 - In a large mixing bowl, using an electric mixer, cream the softened unsalted butter and granulated sugar together until the mixture is light, pale, and fluffy, approximately 2 to 3 minutes.
04 - Add the large eggs to the creamed mixture, one at a time, beating thoroughly after each addition until fully incorporated.
05 - Stir in the fresh lemon zest, fresh lemon juice, and vanilla extract until just combined.
06 - In a separate small bowl, whisk together the whole milk and sour cream or plain Greek yogurt.
07 - Gradually add the dry ingredient mixture to the wet batter in three alternating additions with the milk mixture, beginning and ending with the dry ingredients. Mix gently until just combined, being careful not to overmix the batter.
08 - In a small bowl, lightly toss the fresh blueberries with 1 tablespoon of all-purpose flour to prevent them from sinking. Gently fold the floured blueberries into the cake batter.
09 - Carefully pour the prepared cake batter into the greased and floured 9-inch round cake pan. Smooth the top surface evenly with a spatula.
10 - Bake in the preheated oven for 35 to 40 minutes, or until a wooden toothpick inserted into the center of the cake comes out clean, indicating it is fully cooked.
11 - Allow the baked cake to cool in its pan for 10 minutes before carefully inverting it onto a wire rack to cool completely to room temperature.
12 - While the cake cools, prepare the glaze: In a small bowl, whisk the powdered sugar with 2 to 3 tablespoons of fresh lemon juice until a smooth, pourable consistency is achieved. Drizzle the glaze evenly over the completely cooled cake.
13 - Allow the lemon glaze to set for approximately 15 minutes before slicing and serving the cake.