Whisk eggs yolks together in a small bowl; set aside.
In 2-quart saucepan, whisk both sugars, cornstarch, cinnamon, nutmeg, and salt.
Slowly whisk in milk.
Place pan over medium heat and cook, stirring constantly, until mixture thickens and simmers but doesn’t reach a full boil. (You’ll see a good amount of steam; remove before it bubbles.)
Gradually whisk at least half of the hot mixture into the egg yolks.
Add the egg and milk mixture to the remaining hot mixture in saucepan, whisking constantly.
Bring to a boil, continuing to whisk for approximately 1 minute or until thickened.
Remove from heat.
Stir in pumpkin, butter, and vanilla until butter melts.
Pour pudding into medium-sized bowl.
Cover with plastic wrap (making sure it is flat against the pudding) and refrigerate for 1 hour or until chilled.
Makes 2 cups, approximately 4 or 5 servings.
Notes
For a bit of crunch, serve the pudding with crumbled shortbread cookies or graham crackers.