What I do for baked custard (big batch)
18 eggs and probably 3(up to 5) extra egg yolks
1 gallon of milk
2 cups of sugar (can add more) Less means it's better for you but some like it sweeter
a tablespoon of vanilla
1 teaspoon of ground nutmeg
1/2 teaspoon of salt
optional cup of good rum or bourbon .. can add more.
Teakettle of boiling water, a big casserole dish and the bottom of your turkey roasting pan.
Heat oven to 350
Whip up all the eggs in a bowl. Add everything else except the milk and stir well to mix it all.
Add some of the milk but not all of it. Stir again to mix things.
Find your largest casserole dish to hold it all

Might be able to use the ceramic liner of a crock pot.
Pour the bowl into the casserole dish and now add the rest of the milk to fill. If you don't use the whole gallon that's ok. Stir things around to mix and to dissolve the sugar.
The casserole dish must be surrounded by water to bake. I put the roaster pan in the oven on the rack first. Then i carefully lift the casserole and set it in the roaster without spilling it.
Slide the rack in a bit and then pour boiling water into the roaster until it is at least halfway up the side of the casserole dish. Slide the rack all the way into the oven without sloshing water too much. Close door and bake for around 45 min before checking. Custard should be pretty much set by then. Test the center with a clean butter knife. If the blade comes out coated with liquid, cook it a little more.
When done, I take the casserole out of the water bath and set on the top of the stove to cool a bit before putting in the fridge. Cover the top with plastic wrap. Good warm out of the dish or cold. You can look up recipes to make smaller batches but I want to knock off a lot of eggs at a time and I have pans big enough to do it. I have also set the turkey roaster pan inside my smoker (Traeger) and cooked custard in there outside. That also works and the custard does not come out tasting smokey.
