Preheat the griddle on medium-high heat for 10 minutes.
Toss the potatoes in the oil and salt in a medium bowl.
Add the bacon to the left side of the grill. Cook, stirring occasionally until just beginning to crisp, 3-5 minutes.
Reduce the heat on the right side of the griddle to low, and move the bacon over to the right.
Add the potatoes to the left side of the griddle, on top of the bacon fat. Cover the potatoes with the basting dome. Lift up one edge of the dome and squeeze about ¼ cup of water into the dome to steam the potatoes. Cook, stirring halfway through, until the potatoes are tender and brown, 10–12 minutes.
Meanwhile, once the bacon has browned and become crisp, remove it from the griddle and add the onions, mushrooms, and salt. Cook until the onions are translucent and mushrooms are tender, 4–6 minutes.
Combine the potatoes, vegetables, and bacon and move to the right side of the griddle.
Crack the eggs into a bowl, then pour the eggs onto the griddle. Cook the eggs to your desired doneness, 3–4 minutes for over-easy. Serve the eggs with the hash and top with parsley or chives if you’d like.
