Prepare your campfire or camp stove for indirect heat. You want a steady bed of coals or a medium-low flame. If using a campfire, let the wood burn down to glowing embers—this gives even heat without scorching.

Place a 10-inch cast iron skillet directly on the coals or over the burner. Add the blueberries, 1/2 cup sugar, and lemon juice. Stir gently and cook for 3-4 minutes until the berries start releasing their juices. Remove the skillet from the heat.

In a separate bowl, whisk together the flour, 1 cup sugar, baking powder, and salt. Cut in the cold butter cubes using your fingers or a fork until the mixture looks like coarse crumbs with some pea-sized butter bits still visible.

Pour in the milk and vanilla extract. Stir just until combined—do not overmix. The batter will be thick and lumpy.

Spoon the batter over the hot blueberries in dollops, covering the surface as evenly as possible. It's okay if some berries peek through.

Cover the skillet with a lid or a sheet of heavy-duty aluminum foil crimped tightly around the edges. Place the skillet back over the coals or on the stove. If using a campfire, also place a few hot coals on top of the lid for even heat.

Cook for 20-25 minutes. Check after 15 minutes—the topping should be golden and a toothpick inserted into the dough comes out clean. The blueberries should be bubbling thickly around the edges.

Remove from heat carefully (the handle is hot!). Let the cobbler rest for 5 minutes. Serve warm, straight from the skillet. A scoop of vanilla ice cream or a drizzle of cream is optional but never regretted.