Preheat your oven to 375°F (190°C) and prepare your muffin tin by greasing it or lining it with paper liners.

In a large mixing bowl, whisk together the all-purpose flour, granulated sugar, baking powder, and salt.

In another bowl, beat the softened unsalted butter with the sugar until light and fluffy, about 3-4 minutes.

Add the eggs one at a time to the butter-sugar mixture, mixing well after each addition, then fold in the sour cream.

Gradually fold the dry mixture into the wet ingredients until just combined, with a few streaks of flour remaining.

Gently fold in the fresh blueberries, then fill each muffin cup with batter, add a dollop of cream cheese, and top with more batter.

Bake for 20 to 25 minutes or until golden, then cool in the tin for about 10 minutes before transferring to a wire rack.