Center the oven rack, and preheat the oven to 350°F. Line the bottom of a 9x5-inch loaf pan with a cut out piece of parchment paper. Spray the slides of the pan with baking spray.
Put the blueberries in a small-ish bowl, and toss them with the 2 teaspoons of flour to coat. In a medium bowl, whisk together the 2 cups of four, baking powder and salt. In a large bowl, and working one ingredient at a time, whisk together the eggs, sugar, oil, lemon zest, lemon juice, sour cream and vanilla extract. Add the dry ingredients to the wet, and stir with a large spoon just to combine. Add the blueberries, and gently fold them into the batter.
Scrape the batter evenly into the prepared loaf pan. Bake in the preheated oven until the loaf turns golden, and a skewer inserted into the center of the loaf comes out clean -- 55-60 minutes. Let cool for 20 minutes in the pan, then unmold onto a wire rack, and let cool completely.
For the glaze, vigorously stir the sifted confectioners' sugar and lemon juice together. Add more lemon juice (or water) until a thick but pour-able consistency is achieved. Spoon the glaze over the (thoroughly cooled) loaf. Permit the glaze to set (i.e., harden) for 1 hour. Cut the loaf into thick slices and enjoy it with coffee, tea, or Champagne!