Step 1
In a bowl or measuring cup, whisk milk together with cornstarch and salt until cornstarch dissolves.
Step 2
Whisk cream and sugar together over medium heat in a 1 ½ quart sauce pot and bring to a boil; then whisk cornstarch mixture in until mixture comes to a boil again. Reduce heat to medium low and whisk at least 2 minutes and until thickened. Remove pot from heat.
Step 3
In a bowl or measuring cup, whisk egg yolks then whisk about ½ cup of the thickened milk mixture into the egg yolks to temper them.
Step 4
Whisk the egg yolk mixture into the pot and heat, whisking constantly, until mixture reaches a minimum of 160 F. Do not boil or the pudding will curdle.
Step 5
Stir in vanilla and butter until blended.
Step 6
Transfer pudding into a clean bowl or individual serving dishes. Place a piece of plastic wrap directly over the surface.
Step 7
Chill until cold before serving; at least an hour.
If chilled in a bowl, pudding can be whipped before serving.