Zucchini Casserole

8 medium zucchini, about 4 lbs
1 large onion, thinly sliced
2 cloves garlic, minced
5 ounces parmesan cheese, shredded
1 cup heavy cream or coconut cream
salt & freshly ground black pepper
Butter or olive oil

Slice zucchini using a mandoline or grater.  Sprinkle liberally with salt and set aside at room temperature for a couple of hours.  Drain and wrap in a tea towel to remove excess water.

In a skillet, saute sliced onion in olive oil or butter until caramelized.  Add cream and deglaze pan.  Add garlic.  Mix with remaining ingredients, season with black pepper and place in a large casserole.  Bake at 350 until concoction is browned and bubbling.