If not cooking in a fire, preheat the oven to 500 degrees. 

Heat ⅓ cup of olive oil in a large skillet over medium heat on a stove or over a fire. Add the scallions, and cook for 5 minutes, until they begin soften. Add the spinach and saute until wilted. Remove from the heat and let cool.

Once cooled, add the eggs (if using), 1 tablespoon of salt, and lemon juice. Mix to combine and set aside.

Slice the potatoes in half lengthwise. Using a spoon, scoop out the middle from each half, leaving ½” of the potato inside the skin. Save the scooped out potato pieces for another use. 

On one half of each potato, sprinkle salt, then fill it with ⅓ cup of the scallion and spinach mixture. Take the other potato half, sprinkle it with salt, and press 1 slice of cheddar into the bottom. Close the halves tightly, and tightly wrap the potato with foil.

If cooking with a fire, tuck the potatoes into the bottom center of the bonfire and cook for about 1 hour until charred on the outside and tender on the inside. If using an oven, transfer the potatoes to a sheet tray and roast in the oven for 1 hour to 1 hour and 30 minutes, until fork tender and browned on the outside. Unwrap and serve immediately.