Slice the peppers in half lengthwise and remove the stem and any seeds. If there are any large, thick ribs, remove them as well.

Heat a large, seasoned cast iron skillet over medium-high heat until searingly hot. Reduce the heat to medium and add 2 tablespoons olive oil.

Add the peppers cut side down in a single layer—you may need to fry the peppers in two batches if you can't fit all the peppers in the skillet at once with breathing room around them, so hold on to that extra 2 tablespoons olive oil and

Cook without stirring or moving the peppers for 5 minutes, letting the steam building up under the peppers' "domes" soften them. Flip the peppers with tongs and cook undisturbed for 5 minutes more, letting the skin of the peppers blister and char in the oil.

Continue to cook and flip until the peppers are as soft and blackened as you'd like, anywhere from 5-10 minutes more.

Repeat with the remaining peppers and olive oil as needed.

Transfer the charred peppers to a plate and blanket generously with Parmesan cheese. Serve immediately.