Preheat the oven to 350 degrees Fahrenheit.
Fill 24 muffin cups with paper liners.
To make the cream cheese filling, put cream cheese in a medium sized bowl. Using an electric mixer, beat until soft.
Then add egg, vanilla, cinnamon and brown sugar. Mix until smooth and set aside.
To make the muffins, in a large bowl, whisk together flour, xanthan gum (if using), sugar, baking powder, cinnamon and salt.
Make a well in the center of the dry ingredients and add in the eggs, pumpkin puree, vegetable oil and vanilla.
Mix together until the batter is smooth.
Fill the muffin cups with the pumpkin batter 1/2 way full.
Add a tablespoon of cream cheese to the center of the batter. Try to make sure that the cream cheese does not touch the sides of the muffin.
Top with remaining pumpkin batter.
Bake at 350F for 20 to 25 minutes, or until baked through. You can test this by inserting a toothpick in the center of the muffin. If the toothpick comes out clean, the muffins are ready.