Toss the apples with oil, salt, pepper, and cinnamon. Pour onto a sheet pan or into a baking dish and roast 15-20 minutes or until tender.
Rub steak with the garlic, mustard, salt, and pepper. Let it sit 10-15 minutes.
Heat a pan on medium. Add in a bit of oil and then add the onion. Season and let cook 2-3 minutes. Start adding in the cabbage and cook another 3 minutes. Season and stir in the vinegar, and apple cider. Cover and simmer 20 minutes. Cabbage should be tender, adjust seasoning and remove from heat.
Heat a saute pan, add in bit of oil, and sear steak on each side. Cook until your preferred doneness. Let rest a few minutes. Serve with the apples and cabbage.