In a small bowl add the flour, sugar, and salt, then mix well to combine.

Pour the melted butter on top and use a fork or small spatula to mix into coarse crumbs. Set aside at room temperature until needed.

Preheat oven to 375F and line a muffin tin with cupcake liners.

In a large bowl add the egg and sugar, then whisk well to combine. Pour in the buttermilk, vegetable oil, salt, and vanilla extract. Mix everything well until fully combined.

Sift the flour and baking soda into the wet mixture, then combine with a spatula or whisk.

Toss half of the blueberries with 1 tablespoon of flour, coating them evenly.

Fold the blueberries into the muffin batter, using gentle motions to avoid squashing the fruit.

In a medium bowl add the cream cheese, sugar, and vanilla. Combine with a hand mixer until soft and fluffy.

Place filling into a piping bag fitted with a ½ inch round nozzle.

Place 1 tablespoons of batter into each cupcake liner. Use a teaspoon to make a small dent in the middle of the batter.

Pipe a dollop of cream cheese filling inside each dent in the batter.

Add about ½ tablespoon of batter on top of the cream cheese filling, then smooth it with the back of a spoon.

Sprinkle some streusel crumbs on top, then add more blueberries for decoration.

Bake for 25 minutes or until golden-brown in color.

Once baked, allow to cool for 10 minutes in the tin, then transfer to a wire rack and cool completely.