Melt the butter in a large saucepan over medium heat and then take a couple of minutes to whisk in the sugar until the mix is smooth.  Add the cream and vanilla and gently bring to a boil while whisking.  Reduce the heat and let it simmer (still whisking!),  for about 10 or so minutes until it’s thickened slightly.  Remove from the heat.  As the caramel sauce cools to room temperature, it will thicken beautifully!

If we’re having this for dessert I usually make it before dinner so it can sit and thicken and then still be slightly warm when served.  It will keep in the fridge for at least a week as well – if there’s any left.