Preheat the oven to 350 F degrees. Grease an 8.5x4.5x2.5 inch loaf pan with butter or cooking spray then flour it.
In a large bowl whisk together the 1 1/2 cups of flour, baking powder and salt. Set aside. In another bowl, whisk together the yogurt, sugar, eggs, lemon zest, vanilla extract and vegetable oil.
Add the wet ingredients to the dry ingredients and whisk until combined.
In another small bowl mix together the blueberries with the 1 tbsp of flour. This will prevent the blueberries from sinking to the bottom of the loaf. Gently fold the blueberries into the batter.
Pour the batter into the prepared loaf pan and bake for 50 minutes or until an inserted toothpick in the center of the loaf comes out clean. Each oven is different so baking time could vary greatly. Mine took about 1 hour and 10 minutes to be completely done.
While the loaf is baking make the lemon syrup by cooking the lemon juice and 1 tbsp of sugar in a small saucepan just until the sugar dissolves and the mixture is clear. Set aside.
Make the lemon glaze by whisking the icing sugar, lemon juice and vanilla extract. This glaze needs to be quite runny, so add milk as needed, about a tbsp at a time until the desired consistency is achieved.
When the cake is done, remove it from the oven and allow it to cook in the loaf pan for about 10 minutes. Remove from loaf pan onto a baking rack, then place the baking rack over a baking sheet. Poke holes in the cake using a skewer or toothpick then pour the lemon syrup all over the cake. Allow it to cool.
Once the cake is cooled, drizzle with the lemon glaze, cut into slices and serve.