Preheat the oven to 400 degrees. Place the cast-iron skillet in the oven as it heats up.
Whisk together the eggs, half-and-half, and salt in a large bowl. Set aside.
Add the chopped bacon to a frying pan over medium to medium-low heat. Stir occasionally until bacon bits are crispy—about 10 minutes.
In another smaller frying pan, add 1/2 tbsp butter over medium heat. Once melted, add the frozen hashed brown potatoes. Cook until the potatoes become crispy—about 5 6 minutes. Set aside in a bowl.
Melt the other 1/2 tbsp of butter in that pan, then add the scallions, white onion, and bell pepper. Season with some salt and pepper and cook until the veggies become soft—about 3 minutes. Remove to the same bowl as the potatoes.
When the bacon is ready, add the bits to the bowl with the potatoes and veggies.
Carefully remove the cast-iron skillet from the oven with mitts.
Add in the bowl of potatoes, veggies, and bacon. Spread evenly on the bottom of the pan.
Sprinkle the shredded cheese evenly above the fillings.
Pour in the egg mixture, making sure it coats all of the fixings and is even.
With oven mitts, place the cast-iron skillet carefully back in the oven on the middle rack.
Bake in the oven for 10 minutes.