Preheat oven to 450°F.
Add the potatoes and onions to a baking pan and arrange the Cornish Hens on top. Drizzle each hen with 1 tablespoon of extra virgin olive oil and use 2 tablespoons to drizzle over the vegetables below.
Bake for 20 minutes.
Meanwhile, combine the apple cider and maple in a pan over the stove. Bring to a rolling boil and then simmer. Add cornstarch or flour and whisk until it dissolves. Continue to simmer while the hens are baking.
When the 20 minutes are up, remove the hens from the oven and drizzle 1/2 cup of the cider mix over each hen. Add the mushrooms and slices of apples. (You can reserve some apples for mixing in when the dish is finished cooking.) Lightly cover with tin foil and return to the oven for 20 minutes.
When the time is up, remove the tin foil and bake for another 5 minutes. If you want the skin crisper, broil for 2-4 minutes. Watch it so you don’t burn the skin.
Remove and drizzle the sauce over the hens. Sprinkle with more thyme, fresh parsley, and additional sea salt and pepper to taste.