1. Preheat oven to 350°F. Arrange an oven rack in the middle of the oven.
2. Line a muffin tin pan with muffin liners and set it aside.
3. Blueberry Lemon Muffins:
4. In a medium bowl whisk together: flour, baking powder and salt, set aside.
5. In a large bowl, using an electric mixer beat together butter and sugar until light and creamy.
6. Add eggs, sour cream, milk, lemon juice and lemon zest. Beat until fully combined and creamy. Stop to scrape the sides and bottom of the bowl.
7. Add flour mixture to the wet ingredients and whisk until fully combined. Stop to scrape the sides and bottom of the bowl.
8. Add fresh or frozen blueberries to the batter and using a spatula gently stir to combine.
9. Using an ice cream scoop, spoon batter into prepared muffin pan. The muffins tins should be a little over 3/4 full.
10. Bake for 20-25 minutes, or until a toothpick inserted in the center of a muffin comes out mostly clean, with just a few crumbs attached and no raw batter. Start checking on the muffins after 20 minutes of baking and after 15 minutes if you are making mini muffins. If it still need to bake more, check on the every 3-5 minutes.
11. Once fully baked, remove the muffin pan from the oven and set it on a wire cooling rack. Let the muffins cool in the pan for 10 minutes. Remove from the pan onto the cooling rack. Cool completely before frosting.

Lemon Glaze:

1. Add sugar and lemon zest to a medium bowl, add lemon juice one tablespoon at a time and stir to combine until smooth, with no lumps. If the mixture is too thin, add more confectioners sugar. If the mixture is too thick, add more lemon juice, 1 tablespoon at a time.
2. Drizzle the glaze over the cooled muffins. Let it settle.

3. Store muffins in an air tight container on the counter, at room temperature  for up to 2-3 days.