Whisk together egg and milk in a bowl. Set aside.
Whisk together sugar and cornstarch in a medium pan over medium heat.
Slowly add milk egg mixture to pan, stirring constantly.
Bring to a boil and cook for 1 minute, stirring constantly.
Remove from heat.
Combine remaining ingredients in a bowl and mix well.
Gradually add pumpkin mixture to pan, whisking constantly until blended.
Return pan to low heat and cook for 3-4 minutes until heated throughout, stirring constantly.
Remove from heat, transfer to serving dishes and refrigerate to chill.
Serve with a dollop of whipped cream or whipped topping.