Place the melted butter, sugar, and brown sugar in a medium bowl and mix until completely combined.
Add the pumpkin purée, milk, eggs, and maple syrup and stir.
In a large bowl, sift together the flour, baking soda, baking powder, pumpkin spice, and salt.
Pour the wet ingredients into the dry ingredients and stir until just moistened. DO NOT OVER MIX.
Line a muffin pan with baking liners and use a ¼ cup cookie scoop to fill the muffin tin cups with batter.
Cream Cheese Filling: Beat the cream cheese in a stand mixer or with a hand mixer until light and fluffy. Then combine cream cheese with the sugar, flour, vanilla, and milk. Mix until smooth.
Add the cream cheese mixture to a piping bag, or ziplock bag, and place the tip into the center of the muffin batter. Squeeze the filling out as you slowly lift the piping bag up. You will need about 1-1 ½ tablespoons of filling per muffin.
Optional Topping: Mix the oats and pumpkin spice together, then sprinkle over the top of the muffin.
Bake at 375° for 20-25 minutes, until a toothpick inserted comes out clean.
Allow the muffins to cool for 5 minutes, then transfer them to a cooling rack.