Combine flour, sugars, baking powder and salt in a large bowl.
Stir in milk, egg, butter and lemon zest.
Stir in chips and blueberries.
Spoon into lined muffin pans, filling 3/4 full. Sprinkle with streusel topping.
Bake for 22 to 25 minutes or until wooden pick inserted in center comes out clean.
For Streusel combine: 1/3 cup granulated sugar, 1/4 cup all-purpose flour and 1/4 teaspoon cinnamon in a small bowl. Cut in 3 tablespoons butter with pastry blender or knife until mixture resembles coarse crumbs.