Note: I chose to make my apple crisp in an oven, but by simply placing BBQ brickets under and on top of the lid of your dutch oven you can make this outdoors.
I recommend putting 16 coals on top of the lid and 8 underneath the dutch oven.
Over a fire, the recipe is done when the apples are soft and the toppings are brown - which should be 25 to 30 minutes depending on how hot the coals are when you start.
Find it online: https://experimentalhomesteader.com/dutch-oven-recipe/