1. Heat a grill pan to medium-high.
2. Sprinkle the steak with salt and pepper. Place on the hot grill pan, along with the peppers. Grill the steak, turning once, to desired doneness (about 15 minutes for medium). Transfer the steak to a cutting board and let rest while you prepare the relish.
3. Use a vegetable peeler or your fingers to peel off the thin skin of the bell peppers. Discard the skin, stems, and seeds, then finely dice the peppers.
4. In a medium bowl, stir the vinegar, oil, sugar, and a pinch each of salt and pepper until the sugar dissolves. Stir in the peppers, parsley, and garlic. Serve with the steak.
5. Once the stovetop is cool, wipe up any oil splatters with Clorox® Disinfecting Wipes*.
*Use as directed. For surfaces that may come in contact with food, a potable water rinse is required.