Preheat oven to 450 degrees.

Place pie pastry into glass or ceramic pie plate. Firmly press bottom and sides into plate and finish the edges of the crust by pressing the tines of a fork against the rim of the crust, or by pursing the edges together between your thumb and forefinger. Refrigerate crust until oven has heated completely. Lay a piece of parchment paper over the crust and fill it with pie weights or dried beans. Bake for 10 minutes until set and just starting to brown. Remove crust from oven and set aside to cool

Reduce oven temperature to 350 degrees.

In a large skillet, heat 1½ teaspoons olive oil over medium heat. When the pan is hot, add mushrooms and sprinkle with ¼ teaspoon salt and the red pepper flakes. Sauté for 3-5 minutes or until the mushrooms start to give up their liquid Add onions and bundle of thyme. Cook 2-3 minutes, until vegetables are tender, stirring occasionally. Transfer mixture to a small bowl.

Add remaining oil to the skillet and add chopped kale and ¼ teaspoon kosher salt. Cook 1 minute, stirring. Stir in the water, cover and steam until kale is wilted and water has evaporated, stirring occasionally, 2-3 minutes. Add kale to onion mixture. Set aside.

In a medium bowl add eggs, milk, cream, nutmeg, remaining salt and pepper. Whisk to combine.

Add kale mixture, and grated cheese to the egg mixture. Stir well to combine.

Pour filling into pie crust and spread it out evenly. Top with additional cheese if desired. Bake for 45-60 minutes, or until filling is set. Remove from oven. Let quiche rest for 15 minutes before slicing.