Preheat your oven to 400 degrees and either line your muffin pan with baking liners or spray with non-stick spray.
Mix the milk with the lemon juice and set aside. (If you have buttermilk, you can use that instead of milk and lemon juice)
In a small bowl, whisk together the flour, baking powder, baking powder, and salt.
In a larger bowl, beat together 1 stick of softened butter and sugar until combined.
Add eggs, vanilla extract, and milk mixture to the butter mixture and beat until light and fluffy.
Add half of the flour mixture to the wet mixture, combine, then add the last half of the dry mixture and combine together.
Very carefully fold in the blueberries just until combined being careful to not pop the berries.
Add all of the topping ingredients to a small bowl and cut in the butter with either a pastry cutter or a fork until the mixture resembles wet sand.
Top each muffin with the cinnamon mixture.
Place your muffins in the center rack and immediately turn the oven temperature down to 350 degrees.
Bake for 20-25 minutes. The muffins are done when a toothpick or cake tester comes out clean.
Notes
Note: If you are using frozen blueberries. let your unbaked muffins come to room temperature before putting them in the oven. The muffins will not rise if there are frozen blueberries in them.