In a large bowl put flour, baking powder and salt
Stir together thoroughly
Make a well in center
In another bowl cream butter and sugar
Beat in egg until quite smooth
Mix in milk and vanilla Pour into well
Stir just to moisten
Batter will be lumpy
Stir blueberries with flour lightly
Fold into batter
Fill greased muffin cups 3/4 full
Add streusel topping (see below) if desired.
Bake in 400 degreen oven for 20-25 minutes until nicely browned. Makes 16 muffins (mine only made 12)
After you remove them from the oven losen around the edges.
The streusel topping hardens as it cools and it can make it difficult to remove from the pan.
I just run a toothpick around the edge, pushing the streusel topping off of the pan and onto the muffin