How to Make It
Heat a large, heavy frying pan (not nonstick) or cast-iron skillet over medium-high heat until pan is very hot, about 2 minutes. Add oil and heat until just beginning to smoke. Add peppers (and chile flakes, if using sweet peppers) and cook, stirring occasionally, until blistered in places, 1 1/2 to 2 1/2 minutes. Season with salt.