I made some last week.
In a 5 quart sauce pan.
3 Cups sugar
2/3 cup water
4 oz butter
Cook making sure to dissolve the sugar.
Do not leave the stove, it will start to cook and to become clear with bubbles, first small, then larger and larger and then it settles down again to smaller bubbles, then it begins to brown. Some people and recipes say you can just let it cook without stirring for part of the time--I can't, I don't trust it not to burn.
It can go from a nice caramel color to burnt in just seconds so continue to stir at all times.
Have vanilla 1 tsp. and half and half 1 and 1/2 cups, open and measured and ready to go.
When it looks and smells like caramel, add the vanilla and half and half--it will bubble up and almost fill the pan, be careful and stir. Stir on the heat for another 2 minutes. It should appear thin while hot, if it is too thick, you can add more half and half. Let cool and it will thicken slightly. This made 3+ cups approximately. Enough for a week of ice cream gremlins raiding the fridge/freezer.
Keeps in a jar in the refrigerator.
The whole process took about 20 minutes.
The gremlins want me to make more caramel sauce but I'm thinking I want some hot fudge sauce next.