1Peel the butternut squash and cut it into 1 inch cubes
2In a large pot over low heat add the butternut squash cubes and sugar and toss to distribute the sugar. Cover.
After about 10 minutes you will find that the natural juices of the squash will start to fill the pot. Toss the cubes or gently stir them every 5 - 10 minutes to cook evenly.
It will take about 30 minutes for the squash to be cooked. The cubes should be tender but not mushy. (mine were overcooked this time)
Using a slotted spoon move the cubes to a baking dish leaving the syrup in the pot. Sprinkle the pecans on top of the squash if using them and set aside.
3Preheat the oven to 400 degrees F.
To the syrup in the pot over medium heat add 2 cups milk.
In a measuring cup stir together the remaining 2 cup milk, vanilla and the cornstarch.
4When the pot reaches a slow boil, slowly add the cornstarch mixture while stirring gently. Continue stirring until the pudding returns to boiling and is thickened. Remove from heat.
5Pour the pudding over the butternut cubes making sure it goes in between the cubes then covers the top completely.
Bake till top is lightly browned; about 20 - 30 min.
Chill and serve cold, but some people like it warm.
6If I have any pudding left after covering the casserole I usually pour it into individual bowls and serve as butternut squash pudding.