Mix together condensed milk, half and half, eggs and vanilla in blender or with a mixer.
Melt together butter and brown sugar. Pour into a 9 X 2 round pan or small jello mold. (Double the recipe for larger mold such as a Bundt pan.) Pour pudding mixture on top of sugar mixture. Place pan or mold in a larger pan of water and bake at 325 degrees for an hour and 15 minutes.
Turn over on to serving plate when taken out of oven.
You can use whole milk or 2% milk if you want a lighter dessert.