For the crème fraîche: Stir the buttermilk into the cream and let sit at room temperature for 8 hours or until thick. Refrigerate. Can be made a few days ahead.

For the butterscotch: In a medium-sized heavy-bottomed sauce pot, cook the butter and brown sugar together over medium heat.

Stir with a wooden spoon or carefully whisk. Tip: Be sure to use an egg whisk, or the sugar will get caught in the wires. The sugar and butter will separate at first, but as the sugar melts it will become easier to blend them together.

Cook and stir until the sugar melts and the butter/sugar mixture just starts to brown. It will start to smoke slightly as well.

Slowly add the cream, one cup at a time. It will sputter and seize up as you add the cold cream. Cook the butterscotch until the seized sugar dissolves again. Add the rest of the cream, vanilla bean and salt.

For the custard: In a bowl, whisk together the egg yolks.

Slowly add some of the hot butterscotch-cream to the yolks as you whisk them. You are just adding enough of the warm cream to warm the yolks slightly.

Once the yolks are warm to the touch, pour the yolks back into the pot of hot butterscotch-cream and gently whisk.

Strain the mixture to remove the vanilla bean pieces.

Heat the oven to 325 F.

Divide the custard into eight 4-ounce ramekins. Place them in a water bath and tent with foil. It’s important that the water in the pan is hot and comes halfway up the side of the ramekins, so it will reach oven temperature quickly. Using cool water will prevent them from baking evenly.

Bake for 25-40 minutes. This will depend on the temperature of the mixture when you put them in the oven. Best to check them after 25 minutes and gauge how much longer they need. Unlike a cake, you can open the oven and check them as often as you like without hurting them. The best way to check if they are done is to gently tap the side of each ramekin. If the custard ripples like water, it needs to bake longer. If it moves like set jell-o, then it is done. Be careful not to over-bake them or they will be grainy and “eggy.”

Remove the pan from the oven and allow the custards to cool in the water bath. Once they have reached room temperature, you can remove them from the bath. Cover them and refrigerate for at least an hour. They can be made a few days in advance.

To serve: Spread a thin layer of unsweetened crème fraîche over the top of the custard. You can add a touch of sugar to the crème fraîche if a sweeter topping is desired.