Pat the pork chops dry and season with salt and pepper.
In a large skillet over medium-high heat, heat the oil until shimmering. Add the chops and cook until browned on one side, about 4 minutes. Turn the chops and cook until browned on the other side, about 3 minutes. (If the chops are browning too quickly, lower the heat.) Transfer the chops to a plate and cover to keep warm.
Add the onion to the skillet and stir, cooking until the onion is softened and nearly translucent, 6 to 8 minutes. Stir in the cabbage and cook until the cabbage is tender, 5 to 8 minutes. Add the butter, if using, and toss to coat the cabbage. (If the chops are lean, butter will enhance the flavor.) Transfer the cabbage mixture to a serving platter and cover to keep warm.
Lower the heat to medium. Add the cream and mustard to the skillet and stir until the mustard is fully incorporated, about 1 minute. Add the lemon juice and white pepper; stir to combine
Add the chops back to the skillet. Lower the heat to medium-low and simmer until the sauce thickens slightly, about 5 minutes, basting the chops with the sauce.
Place the chops on top of the cabbage on the serving platter. Drizzle the chops and cabbage with the remaining sauce, garnish with the parsley and serve.