Preheat the oven to 400°F, and line the muffin pan with the liner. Line the pan in an alternate order. Leave one empty cavity between the muffin liners.
Whisk all the dry ingredients together. set aside.
2 cups All-purpose flour, 1 tablespoon Baking powder, 1 teaspoon Baking soda, ½ teaspoon Salt
Add the orange zest to the sugar and massage it with your fingertips to release the orange aroma from the zest. Add this to the dry ingredients and mix.
1 cup Sugar, 2 teaspoon Orange zest
Whisk the sour cream, orange juice, eggs, oil, and vanilla extract in a separate bowl using a hand whisk or a fork.
½ cup Sour cream, ¼ cup Oil, 2 Eggs, ¼ cup Orange juice, 1 tablespoon Vanilla extract
Add the dry ingredients to the above mixture, and mix until no trace of flour is seen.
Fold in the blueberries and mix gently.
2½ cup Blueberries
Leave the batter on the counter for 10-15 minutes. This contributes to a fuller and domed shape muffin top.
Scoop the batter into the muffin cups, and fill the cups to the top.
Cover the top of muffins with the topping streusel, and bake for 25 minutes or until an insert comes out clean. let cool in the muffin pan, then transfer to a cooling rack.