In a medium-size bowl using an electric mixer, mix together the butter and sugars until light and fluffy. Beat in the egg and then mix in the sour cream.
in a separate medium-size bowl whisk together the flour, graham cracker crumbs, salt, baking powder, baking soda, and cinnamon.
Add dry mixture to the creamed mixture alternately with the milk until just moistened, and then fold in the chocolate chips.
Lightly spray 6 muffin cups with cooking spray, and fill the other 6 half full of water. Fill muffin tins ¼ full of batter followed by 1 tablespoon of marshmallow cream. (I sprayed the measuring spoon with cooking to help keep the marshmallow cream from sticking.) Divide the remaining batter between the 6 cups over the top of the marshmallow cream.
Bake for 14 – 16 minutes or until a tooth pick inserted comes out clean. Let the muffins cool for 5 minutes and then place them on a wire rack.