Preheat oven to 375F. Place pie crust on a baking sheet and prick all over with a fork. Blind bake for 10 minutes.
Meanwhile, make spinach filling. Melt the butter in a non stick pan over medium heat. Add the shallot and cook for about 2 minutes until it begins to soften. Add the spinach and ¼ tsp salt and freshly ground pepper. Cook another 2-3 minutes until spinach is wilted.
Transfer spinach mixture into a sieve, using the back of a spatula, push and stir the mixture to draw out excess liquid. I do this about 6-8 times or until barely any liquid comes out. Spread evenly in the bottom of the crust and sprinkle cheese evenly over the spinach.
In a large bowl, whisk together the cream, milk, eggs with remaining salt and pepper. Pour over the spinach and cheese.
Bake for 30 minutes in a 375F oven until quiche is golden brown and still slightly jiggly.