Step 1

Preheat the oven to 350º Fahrenheit. Spray an 8x8 baking pan with cooking spray.

Step 2

In a large bowl, cream the butter and sugar together using a hand mixer, scraping the sides of the bowls as needed.

Step 3

Add the egg and beat well.

Step 4

In a small bowl, whisk together the flour, baking powder and salt.

Step 5

Add the flour mixture alternately with the milk, mixing between each addition.

Step 6

Fold in the blueberries.

Step 7

Spread the batter in the prepared pan.

Step 8

In a small bowl, use a fork to mix together the butter, sugar, flour and cinnamon until it resembles coarse crumbs.

Step 9

Sprinkle the crumbs over the cake batter.

Step 10

Bake for 33-35 minutes or until the cake tests done.