Preheat oven to 425°. Spray a 12-cup muffin pan with cooking spray.
For batter: In a large bowl, whisk together flour, sugar, baking powder, baking soda, and salt.
In a medium bowl, whisk together buttermilk, oil, egg, orange zest, and vanilla until smooth. Stir buttermilk mixture into flour mixture just until combined. Stir in blueberries. Spoon batter into prepared cups.
For topping: In a small bowl, stir together all ingredients until crumbly. Sprinkle onto batter.
Bake until golden brown and a wooden pick inserted in center comes out clean, 18 to 20 minutes. Let cool in pans for 10 minutes. Remove from pans, and let cool on a wire rack.
For glaze: In a small bowl, whisk together confectioners’ sugar and orange juice until smooth. Drizzle onto muffins.
Recipe by Paula Deen Magazine at https://pauladeenmagazine.com/glazed-streusel-topped-blueberry-muffins/