Prepare the campfire or camp stove: Build a small fire and let it burn down to hot coals, or set up a camp stove with a cast iron skillet.
Core and slice the apples into 1/4-inch thick wedges. Toss with lemon juice, 1/4 cup brown sugar, cinnamon, and nutmeg.
For the skillet crisp: In a separate bowl, mix oats, flour, remaining 1/4 cup brown sugar, and nuts. Cut in cold butter until crumbly.
Layer the seasoned apples in a greased 10-inch cast iron skillet. Sprinkle the oat mixture evenly over the top.
Place the skillet on hot coals or over medium-low heat on a camp stove. Cover with a lid or foil. Cook for 20-25 minutes, rotating occasionally, until apples are tender and topping is golden.
For foil packets: Divide the seasoned apples among four large sheets of heavy-duty foil. Top each with a tablespoon of the oat mixture. Fold foil into tightly sealed packets.
Cook packets on hot coals for 15-20 minutes, flipping once. Let rest 2 minutes before opening carefully (steam is hot!).
For spiced cider: In a small pot, combine apple cider, cinnamon sticks, and cloves. Heat over campfire or stove until steaming (not boiling). Simmer 10 minutes, then remove spices.
Serve the crisp or foil packets warm, optionally with a dollop of yogurt or a splash of cream. Enjoy the cider straight from a camp mug.
