Grandma's Blueberry Streusel Coffeecake

My grandma cut out this recipe from the Daily Herald newspaper many years ago. I think it may be the best coffeecake I've ever had.

• Ready In: 1 hr 15 mins
• Serves: 8

Ingredients

• Streusel Topping

• 1⁄2 cup sugar
• 1⁄3 cup flour
• 1⁄3 teaspoon salt
• 1⁄2 teaspoon cinnamon
• 4  tablespoons butter

• Cake

• 2  cups flour
• 2  teaspoons baking powder
• 1⁄2 teaspoon salt
• 4  tablespoons butter, room temperature
• 3⁄4 cup sugar
• 1  egg, room temperature
• 3⁄4 cup milk
• 1  teaspoon vanilla extract
• 2  cups fresh blueberries

Directions

1. Preheat oven to 385 degrees. Grease a 9- or 10-inch pie plate.
2. For the streusel topping, use a fork and a small bowl to blend the sugar, flour, salt, cinnamon and butter until crumbly. Set aside.
3. For the cake, sift together flour, baking powder and salt into a medium bowl.
4. In a large bowl, cream the butter and sugar. Add the egg, milk and vanilla and beat until smooth. Mix in the dry ingredients, then fold in the blueberries.
5. Spread cake mixture into prepared pie dish and sprinkle with streusel topping. Bake 50-60 minutes or until golden. Allow to cool for 20 minutes before slicing. Serve warm, if possible.