In a medium bowl, whisk together the flour, baking powder, salt, and cinnamon. Set aside.
In the bowl of a stand mixer fitted with the whisk attachment or in a large bowl with a hand mixer, beat together the sugar and butter on high speed for 2 minutes, until lightened. Add the eggs one at a time, beating to incorporate between each addition. Beat in the vanilla extract.
Add half of the dry ingredients to the butter mixture and beat on medium speed until blended. Add ¼ cup of the milk and mix until blended. Repeat with the remaining dry ingredients, followed by the remaining ¼ cup of milk. Beat until well blended; the batter will be thick.
Use a spatula to gently fold the blueberries into the batter until just combined. Divide the batter evenly between the lined muffin cups. It will seem like too much batter, but it works.
Top each muffin with about 1 tablespoon of the crumb topping, keeping it toward the center of the muffins since the muffins spread and grow (and so will the crumbs).
Bake for about 25 minutes, or until the tops of the muffins are golden and a toothpick inserted into the center comes out clean. Let the muffins cool in the muffin tin for 10 minutes, then transfer to a wire rack and enjoy.