The vegetable side has a slightly sweet-and-sour flavor.
Halve, core, and thinly slice red cabbage.
Heat olive oil in a large skillet over medium heat. Add cabbage and red-wine vinegar; season with coarse salt and ground pepper. Cook, tossing frequently, until cabbage is crisp-tender, about 15 minutes (add a splash of water if pan becomes dry).
Add light-brown sugar; toss until dissolved, about 30 seconds. Season again with salt and pepper, as desired.