Potato, Spinach, & Mushroom Casserole - cooking recipe

Ingredients

6 large baking potatoes (about 3 lbs I have also used 3 lbs of red potatoes. Your preference.)
6 tablespoons olive oil
4 cloves garlic, minced
1 1/2 teaspoons salt
3/4 teaspoon ground black pepper
1 medium onion, chopped
3/4 lb fresh white mushroom, sliced thin
1 1/2 lbs spinach, stemmed & washed
1 1/2 cups ricotta cheese
1/2 lb gruyere cheese, shredded

Preparation

Preheat oven to 400.
Grease 2 large baking sheets& set them aside.
Scrub potatoes under cold water.
Do not peel.
Cut potatoes lengthwise into 1/4 inch thick slices.
Place slices in a large bowl.
Add 4 T olive oil, garlic, salt and pepper to bowl.
Toss the potatoes gently coating them as best you can.
It is easiest to do by hand, but a little messy.
Once tossed, lay potatoes out on prepared baking sheets.
Try not to overlap.
Cover pans tightly with aluminum foil& bake for 30 minutes (see below what to do while potatoes are baking).
When done, remove pans from oven.
Uncover to cool.
Do not turn oven off.
While potatoes are baking, heat remaining 2 T oil in a large pot.
Add onions and cook over medium heat until soft (about 5 minutes).
Add mushrooms until they throw off their juices (about another 5 minutes).
Stir in spinach.
then add salt& pepper to taste.
Cover and cook til spinach wilts (about 4 minutes).
Uncover and cook off any liquid in the pot.
Remove the pot from heat and stir in ricotta.
Grease a 13 X 9 inch baking pan.
Line the bottom of pan with 1/3 of potatoes.
Spoon 1/2 spinach mixture over layer of potatoes& sprinkle with 1/3 of cheese.
Make another layer of potatoes, cover with remaining spinach mixture& another 1/3 of the cheese.
Lastly, cover with remaining potatoes& sprinkle the rest of the cheese.
Bake until the casserole turns golden brown on top.
Approximately 25 minutes.
Remove pan from oven& let settle for 5 minutes before cutting up slices.