Preheat your oven to 350°F and position the oven rack in the center. Lightly coat a 9x5-inch metal loaf pan with nonstick cooking spray. Line the bottom with parchment paper for easy removal, then spray the parchment and sides of the pan again to ensure nothing sticks.

In a small bowl, combine the milk, lemon zest, and lemon juice. Set this mixture aside for at least 10 minutes while you prepare the rest of the ingredients—it will curdle slightly, which is completely normal and helps add flavor and tenderness to the cake.

In a medium bowl, whisk together the 2 cups of flour, baking soda, and salt. In a separate small bowl, toss the blueberries with the remaining 1 teaspoon of flour to help prevent them from sinking during baking. Set both bowls aside.

Using a stand mixer fitted with the paddle attachment (or a handheld mixer), cream the softened butter and granulated sugar on medium speed until the mixture becomes light and fluffy, about 2 to 3 minutes. Scrape down the sides of the bowl to ensure everything is well blended. Add the eggs one at a time, beating well after each addition, then scrape down the bowl again to maintain an even consistency.

With the mixer on low speed, begin incorporating the dry and wet ingredients in stages: first add one-third of the flour mixture, then half of the milk-lemon mixture, followed by another third of the flour, then the rest of the milk mixture, and finally the remaining flour mixture. Scrape down the bowl as needed throughout this process to keep everything smooth and uniform.

Once the batter is mixed, gently fold in the flour-coated blueberries using a rubber spatula, stirring just until evenly distributed. Transfer the batter into the prepared loaf pan and smooth out the surface with the spatula.

Bake for 50 to 60 minutes, or until the top is golden brown and a toothpick inserted into the center comes out clean. Allow the cake to cool in the pan for about 10 minutes, then carefully remove it and place it on a wire rack to cool completely. Once fully cooled, move the cake to a serving platter.

To make the glaze, combine the confectioners' sugar, lemon zest, and lemon juice in a small bowl. Stir until smooth and adjust the consistency as needed—add a bit more sugar if it's too thin or a touch more lemon juice if it's too thick. The glaze should be thick but pourable, with a texture similar to honey or molasses.

Drizzle the glaze generously over the top of the cooled cake, letting it drip naturally down the sides. Let it set for 10 to 15 minutes before slicing. For the cleanest slices, use a serrated knife. Store any leftovers at room temperature, wrapped in plastic wrap or kept in an airtight container, for up to 3 days.