Blueberry Buckle Ingredients Streusel: ½ cup (2.5 oz) all purpose flour ⅓ cup packed (3/5 oz) light brown sugar 2 Tb granulated sugar ¼ tsp cinnamon pinch of salt 4 Tb unsalted butter, cut into 8 pieces and softened Cake: 1½ cups (7.5 oz) all purpose flour 1½ tsp baking powder 10 Tb unsalted