In a large bowl, combine the flour, sugar, baking powder and salt. In another bowl, beat the eggs, milk and butter; stir into dry ingredients just until moistened. Fold in the blueberries. Spoon about 2 round tablespoonfuls into greased muffin cups.
In a small mixing bowl, beat cream cheese, egg, sugar and salt; place about 1 tablespoon in the center of each muffin cup (do not spread). Top with remaining batter. Bake at 375 degrees F for 18-20 minutes or until a toothpick inserted in muffin comes out clean.
Cool for 10 minutes before removing from pans to wire racks