Line an 8 x 8 inch baking pan with foil. Measure all ingredients ahead of time and have them within easy reach.
In a medium saucepan, combine sugar, butter and heavy cream over medium heat.
Bring to a boil and boil for exactly two minutes, stirring constantly. Remove from heat and immediately stir in marshmallow cream.
As soon as the marshmallow cream is incorporated, add the pumpkin, pumpkin pie spice, and white chocolate chips. Stir the mixture until the white chocolate chips have melted and the mixture is smooth. It will take a bit of stirring.
Stir in 1 cup of the crushed Oreos. Pour into the prepared baking pan. Press the remaining 1 cup of Oreo's onto the surface of the fudge. Cover and Chill overnight. Cut into 1 inch squares.