Start by making the crumb topping. Add all of the ingredients to a medium-size bowl and using a pastry knife, or a fork, cut in butter with the other ingredients until it is about the size of rice. Set aside.
For the muffins, mix the salt, baking powder, baking soda, and 5 cups of flour together until completely mixed together. Set aside.
Next, in a separate medium-size bowl whisk together the milk and oil and set aside.
In a stand mixer with the paddle attachment cream together butter and the sugars on medium speed until light and fluffy, about 5-7 minutes.
Add in 1 egg at a time until completely mixed in and then add in the vanilla.
Turn the speed down to low and alternate in three batches adding in the dry flour ingredients with the wet milk ingredients just until mixed in.
In a medium-size bowl quickly toss the blueberries with 3 tablespoons of flour until coated and then add them to the mixing bowl the batter and fold them in using a rubber spatula until combined.
Evenly distribute the batter between 12 jumbo muffin cups.
Sprinkle on the crumb topping evenly to cover the tops of each muffin.
Bake at 375° for 30-35 minutes or until the tops are lightly brown and firm in the center.
Cool on a rack until room temperature before serving.
Notes
Chef Notes:Make-Ahead: You can make these muffins up to 1 day ahead of time.How to Store: Cover and keep in the refrigerator for up to 5 days. Cover and freeze for up to 3 months. Thaw in the refrigerator for 1 day before serving. You can also leave these covered at room temperature for up to 3 days.If you are using a regular standard 12 muffin tin cut the recipe in half and reduce the amount of baking time by 5-7 minutes.You can substitute the stand mixer with an electric hand mixer.Add the zest and juice of 1 lemon after adding the vanilla in the procedures for a bright lemony flavor.