Preheat oven to 375°F. Grease a 12 count muffin tin.
In a large bowl, combine flour, baking powder, baking soda and salt. Set aside.
In a separate bowl, whisk, sour cream, sugar, lemon juice, lemon zest, eggs, almond extract and melted butter.
Pour the wet ingredients over the dry and carefully stir with a rubber spatula until the two mixtures are just combined (it will be thick and a little lumpy - that's ok - don't overmix). Carefully stir in the blueberries.
Evenly divide the batter among the muffin cups. Bake for 15-18 minutes, until a toothpick inserted into the center comes out clean. Place the pan on a wire rack to cool for 5-10 minutes, then remove each muffin to cool completely.
Whisk all ingredients until smooth. Adjust powdered sugar and lemon juice, as necessary to get your desired consistency. Drizzle icing over cooled muffins.
These muffins are the best the day they are made. Reheat briefly in a toaster or microwave if you're enjoying them in the days following.