Preheat the oven to 350°F and set an oven rack in the middle position. Spray a 9x5-inch metal loaf pan with nonstick cooking spray. Line the bottom of the pan with parchment paper, then spray the pan again.
In a small bowl, whisk together the milk, lemon zest, and lemon juice. Let sit for at least 10 minutes while you proceed with the recipe. (It will curdle; that's okay.)
In a medium bowl, whisk together the 2 cups flour, baking soda, and salt. In a small bowl, toss the blueberries with the remaining teaspoon of flour. Set both aside.
In the bowl of an electric mixer fitted with the paddle attachment (or beaters), cream the butter and sugar on medium speed until light and fluffy, 2 to 3 minutes. Scrape down the sides of the bowl, then beat in the eggs one at a time, beating well after each addition. Scrape down the sides of the bowl again. With the mixer on low speed, beat in a third of the flour mixture, then half of the milk mixture. Beat in another third of the flour mixture, then the remaining milk mixture, followed by the remaining flour mixture, scraping the bowl as necessary. Add the flour-dusted blueberries to the batter and, using a spatula, fold until evenly combined.
Transfer the batter into the prepared pan and smooth the top.
Bake for 50 to 60 minutes, until the cake is golden brown and a tester comes out clean. Let the cake cool in the pan for about 10 minutes, then turn out onto a rack to cool completely.
When the cake is cool, transfer it to a serving platter.
Make the glaze: In a small bowl, mix together the confectioners' sugar, lemon zest, and lemon juice. Add more confectioners' sugar or lemon juice as necessary to make a thick but pourable glaze (it should be a little thicker than you'd think, about the consistency of molasses or honey). Spoon the glaze over the top of the cake, letting it drip down the sides. Let the glaze set for 10 to 15 minutes before serving. Slice with a serrated knife. The cake will keep on the countertop for up to 3 days; store in a covered container or wrap in plastic wrap.
Freezer-Friendly Instructions: The cake can be frozen (without the glaze) for up to 3 months. After it is completely cooled, double-wrap it securely with aluminum foil or plastic freezer wrap, or place it in heavy-duty freezer bag. Thaw overnight on the countertop before serving. (Add the glaze after the cake is thawed.)
Note: You'll need 2 large lemons for the entire recipe. Be sure to zest them before you juice them.