Preheat oven to 400°F. Line 18 muffin cups with paper liners.
In a large bowl, whisk together whole wheat pastry flour, sugar, baking powder, and salt. Work in the softened butter with an electric mixer or fork. Blend in the eggs, milk, lemon juice, vanilla, lemon zest, and lemon extract (if using) until all ingredients are incorporated, but do not overbeat. Gently fold in the blueberries. Evenly divide the batter between the 18 prepared muffin cups.
Bake for 18 to 23 minutes or until the muffins just test done with a toothpick, taking care not to overbake. After a few minutes, remove the muffins from the pans and cool on a wire rack, or eat them warm out of the oven with a pat of salted butter.
You may use frozen blueberries in these muffins, but don't thaw them first. Doing so will just make them all mushy.
This recipe comes together quickly in the bowl of a stand mixer, but you can also mix it in a bowl by hand if you prefer.
For an extra special touch, sprinkle the muffins with coarse sparkling sugar before baking.