Start your campfire or heat up your grill so that your heat source is ready. If using wood or charcoal, let the flames die out prior to cooking your food.
( Optional) Preheat your cast iron skillet over the fire while getting your supplies ready.
Chop your peaches and put in a bowl with the berries. Marinate in some white balsamic vinegar for 10-15 minutes.
Drizzle olive oil in the bottom of your cast iron skillet.
Place wheel of brie in the middle of the skillet and top it with the fruit, allowing them to spill around the sides as well.
Set the cast iron skillet on a grate over the fire and allow it to cook until the brie has puffed up and the fruit has cooked (roughly 20 minutes).
Pull the skillet off the fire and allow to cool slightly.
Serve with baguette slices.