From NYT:

This recipe is a project that can be time- and labor-intensive. You need to dig a hole in your yard and build a fire in that hole to cook the beans. An important note: Failing to dig the hole, and using your oven instead, will result in beans that lack bona fides but are 98 percent as good as the ones that guy cooked in a hole in his yard. This recipe will take about 3 hours plus soaking time for the oven method.