Firm caramels and half and half are the only ingredients needed to make this recipe. (I don't count water as an ingredient.) If you prefer a vanilla caramel, add a teaspoon to the batch. It makes for a lovely 3-Ingredient Caramel Sauce.
Place caramels and water into a 2 quart heavy-bottomed sauce pot. Heat over medium-low heat until the caramels melt. Stir constantly to prevent the caramels from burning.
Once all the caramels have melted and the mixture is smooth, add the half and half. The sauce will bubble up and then settle down. Stir to combine.
Remove the pan from the heat and stir in the vanilla extract if desired. Pour sauce into two heatproof jars.
Store caramel sauce in the refrigerator for up to four weeks.