Blueberry Sour Cream Coffee Cake

2.50 tablespoons coconut sugar, or brown sugar

1/4 cups all-purpose flour

3/4 teaspoons cinnamon

1.50 tablespoons salted butter, melted and cooled

2.50 tablespoons or 2 2/3 tablespoons salted butter, softened to room temperature

1/4 cups coconut sugar, or replace with white sugar

2/3 egg, room temperature