Find a heat-resistant dish that fits inside of your crock pot insert. Fit it in and, using a cup or pitcher, pour water around the edges so there is water 1/2 to 3/4 of the way up the sides of the dish. Push it down with your hand if it starts to float up. Take the dish back out. If you have separate dessert ramekins, do the same thing after nestling them all inside.
Whip the 5 egg yolks in a medium-sized bowl and slowly add the cream and baking sugar while mixing. Add the vanilla. Pour mixture into the dish and carefully lower into the stoneware without sloshing water into the dish.
Cover and cook on high for 2-4 hours. If you are using little ramekins, check after an hour. Custard should be set with the center still a bit jiggly. Touch lightly with your finger to check. Unlike an oven, it will be difficult to overcook this, so don't worry about it too much.
VERY carefully (use oven gloves!) remove dish and let cool completely on counter, then chill in the refrigerator for 2-3 hours.
Sprinkle the 1/4 cup of raw sugar evenly over the top of the custard. Move your oven rack to the top rung and broil for 3-10 minutes, checking often. The sugar will boil and brown.
Cool again in the fridge for a few hours.