Upside Down Tart of Cheese, Onions, and Potatoes

Upside Down Tater Tart

Serve this with a salad, or as a side for a nice steak, or even at brunch. Are you kidding me, potatoes, onions, and lots of cheese . . . now who wouldn't like that?

2-1/2 tablespoons butter
6 sprigs thyme, strip the leaves from the stems
1 teaspoon fresh tarragon
1 large yellow onion, sliced ¼-inch thick
1 pound small red potatoes, washed and very thinly sliced
2 tablespoons olive oil
1/2 cup grated gruyère
1/2 cup crumbled feta
1 cup grated mozzarella
Sea salt and cracked black pepper
Preheat oven to 400°. Melt the butter in a 9-10 inch cast iron skillet (or oven proof pan) over medium heat. Add the thyme, tarragon, and onion; cook for 5 minutes. Place the potato, oil, cheeses, salt and pepper in a bowl and toss to combine.
Top the onion mixture in skillet with the potato mixture and bake for 45 minutes or until golden brown and cooked through. Turn upside down to serve.