Preheat oven to 350 degrees F. Line 2 12-cup muffin pans with paper liners; set aside.
In a large bowl, combine flour, sugars, pumpkin pie spice, baking powder, baking soda and salt.
In a large glass measuring cup or another bowl, whisk together pumpkin puree, vegetable oil, eggs and vanilla.
Pour mixture over dry ingredients and stir using a rubber spatula just until moist; let stand for 15 minutes.
Scoop the batter evenly into the muffin tray.
Squeeze about 2 tablespoons cream cheese filling into the center of each muffin, leaving a dollop on the top; sprinkle with rolled oats around the filling, if desired.
Place into oven and bake for 17-22 minutes, or until a tester inserted in the center comes out clean; let cool 10-15 minutes before transferring to a wire rack.
for the cream cheese filling
In a small bowl, whisk together cream cheese, confectioners' sugar, flour, milk, vanilla and salt until smooth. Transfer to a piping bag or Ziploc bag with the corner snipped off.