Preheat the oven to 375℉ and grease the bottom of a springform pan and cover the bottom with foil. Set aside.
Whisk all dry ingredients and set aside.
2 cups All-purpose flour, 2½ teaspoon Baking powder, ½ teaspoon Salt
Add the orange zest to the sugar and rub it with your fingertips to release the citrus aroma.
1 tablespoon Orange zest, 1 cup Sugar
Beat the soft butter and sugar for 2-3 minutes until light and fluffy.
½ cup Butter
Add the eggs one at a time and beat after each one. Add the vanilla extract and beat for another 2 minutes.
2 Eggs, 1 tablespoon Vanilla extract
In a separate measuring cup, mix the milk, orange juice, and oil.
¼ cup Orange Juice, 2 tablespoon Oil, ½ cup Milk
Switch to a rubber spatula, fold in ⅓ of the dry ingredients, and gently mix. Alternate with the wet ingredients in three passes. Start and finish with dry ingredients.
Fold in the blueberries. Do not overmix.
2 cups Blueberries
Spread the batter into the prepared pan. Cover the top with the streusel and bake for 50-55 minutes or until an insert comes out clean. Let the cake cool down in the pan for 15-20 minutes. Open the springform and transfer the cake to the cooling rack to cool down completely.