Preheat the oven to 375°F (190°C) and prepare your muffin tin.

In a bowl, whisk together all-purpose flour, whole wheat flour, granulated sugar, baking powder, baking soda, and salt.

In another bowl, beat melted butter and cream cheese until smooth.

Add eggs one at a time, mixing thoroughly after each addition.

Stir in vanilla extract and milk until fully combined.

Pour the creamy mixture into the dry ingredients and mix gently until no dry flour is visible.

Fold in fresh blueberries gently to avoid squishing.

Scoop the batter into the muffin cups, filling them about two-thirds full.

Bake for 18-20 minutes, or until golden brown and a toothpick comes out clean.

Let muffins cool in the pan for 5 minutes before transferring to a wire rack.