Preheat oven to 400 degrees F. Grease a muffin pan or line with muffin cups.
In a large bowl, combine the dry ingredients: flour, baking powder, and salt.
In a second large bowl, or stand mixer, add eggs and sour cream. Mix until eggs are broken and mostly combined. Add butter, sugar, milk, vanilla, lemon juice and zest, and mix until well combined.
1 cup at a time, add the dry mixture into the wet ingredients, stirring after each addition. Mix until well combined. The batter may be a bit lumpy. Using a spoon, fold the blueberries into the batter.
Spoon batter into muffin tins until ¾ full.
Crumb Topping: In a small bowl, add all the crumb topping ingredients. With a spoon or your hands, mix the ingredients, breaking up any large lumps.
Sprinkle about 2 tablespoon of the crumb topping onto the muffins in the tins. Very lightly press a little into the batter just enough to keep them from rolling off when baking.
Bake in the oven for 18-25 minutes. Allow to cool for a few minutes before removing to a wire rack to cool completely.