Boil apple cider in pan for about 28 minutes, or until it has significantly reduced. Add applesauce and honey, whisk until incorporated. Add salt. Set aside.
Preheat oven to 425°F. Butter 2 large rimmed baking sheets. Toss onion wedges in large bowl with 2 teaspoons oregano and 3 tablespoons apple cider mixture. Arrange in single layer on 1 sheet. Toss apples in 2 teaspoons oregano and 3 tablespoons apple cider mixture. Arrange in single layer on second sheet. Sprinkle both with pepper.
Roast onions for 10 minutes. Roast apples for 20 minutes.
Remove both sheets from oven. Drizzle remaining apple cider mixture evenly over onions and apples. Roast for an additional 20 minutes.
Increase the temperature to 475°F. Roast onions and apples for about 10 minutes, until tender and lightly browned. Sprinkle with remaining 2 teaspoons of oregano.
Serve and enjoy!