You'll never buy hot fudge sauce again once you see how easy (and delicious) it is to make your own. Drizzle over your favorite ice cream or use as a dip for bananas, strawberries, pineapple, or other favorite fruits.
Chop the chocolate into small chunks about the size of large chocolate chips.
In a small saucepan over low heat, combine the cream, sugar, and butter. Stir until the butter is melted and the sugar is completely dissolved, about 2 minutes. The moment you see bubbles at the edges of the pot, remove it form the heat and turn off the stove.
Pour the chocolate chunks into the warm cream and add the vanilla. Let the mixture sit for 2 minutes (don't stir it). After 2 minutes, stir until smooth.