Preheat oven to 425 degrees then line a baking sheet with foil. Rub poblano peppers lightly with oil then place on baking sheet and roast for 20 minutes, flipping halfway through, or until poblano pepper skin is evenly charred. Immediately transfer peppers to a plastic ziplock bag then let steam for 10-15 minutes. Once cool enough to handle, peel away skin then open peppers and remove the seeds. Chop the peppers then set aside.

Meanwhile, brown sausage in a large skillet over medium-high heat then drain if necessary, and then set aside to cool slightly.

In a very large bowl, whisk together eggs, milk, salt, pepper, and Tabasco sauce (if using.) Add the green onions and chopped peppers then whisk to combine. Add the cooked sausage, hash browns, and 3/4 of the shredded cheese then stir to combine. Pour mixture into a nonstick sprayed 9x13" baking dish then sprinkle remaining cheese on top and cover with foil.

Turn oven down to 350 degrees then bake casserole, covered, for 1 hour and 10 minutes (it's ok if some liquid remains on top.) Remove foil then continue baking until cheese is golden brown and bubbly, 15-20 more minutes.