Combine the sweetened condensed milk and pumpkin in a heavy bottomed pot. Cook over low heat for 10 minutes, stirring almost continuously.

Stir in the white chocolate chips. Continue cooking over low heat, stirring frequently, until the chocolate has melted.

Stir in the pumpkin pie spice and cook an additional five minutes, stirring frequently.

Pour into prepared pan and refrigerate for at least four hours before cutting into squares and serving.

If you want to add the chocolate drizzle, melt white chocolate chips and shortening together and drizzle over the top of the cut pieces of fudge.

Store leftovers in an airtight container in the fridge.