Preheat the oven to 350°F. Line the bottom and sides of a 9" x 5" loaf pan with parchment paper; set aside.
In a medium bowl, sprinkle 1 teaspoon of flour over the blueberries and toss together to gently coat the blueberries with the flour. Set aside.
In a large bowl, whisk together the remaining 2 cups of flour, baking soda, salt, and lemon zest.
In the bowl of a stand mixer with paddle attachment -- or in a large mixing bowl using a hand mixer -- cream the butter for 1-2 minutes. Then add the granulated sugar and cream together for 2-3 minutes, until light and fluffy.
Beat in the eggs until incorporated. Then beat in the lemon juice and vanilla.
Gradually add one-third of the dry ingredients (the flour mixture), then one-third of the buttermilk, and alternate until both are incorporated fully into the batter.
Use a silicone spatula or wooden spoon to gently fold in the floured blueberries, just until they're incorporated.
Pour the batter into the prepared loaf pan.
Bake at 350°F for 50 to 60 minutes, or until a toothpick inserted into the center of the loaf comes out clean
Allow the cake to cool in the pan at room temperature for 10 minutes, then transfer to a wire rack and allow to cool completely. Meanwhile, make the glaze.
Make the Glaze
In a medium bowl, whisk together the powdered sugar, lemon juice, and lemon zest, until smooth. The glaze should be slightly thick, but still drip from the whisk enough to slowly drizzle over the cake. If the glaze is too thin, whisk in a little more powdered sugar; if your glaze is too thick, whisk in a little more lemon juice or water.
Once the cake is completely cool, use a spoon or fork to drizzle the glaze over the top of the cake. Leave the cake and allow the glaze to set before slicing into the loaf.
Notes
Makes approximately 12-15 servings (serving size: 1 slice)Storage: once the cake is cool and glaze is set, cover with plastic wrap or place in an airtight container, and refrigerate for up to three days. Freeze: You can freeze an unglazed cake in an airtight freezer-friendly ziplock bag or container for up to two months.