Add remaining oil to the pan and increase heat to medium high. Add mushrooms and cook, stirring occasionally, until they have released their moisture and begin to brown, about 6 minutes. Add the kale back to the pan, stir in the salt, pepper, mustard, and thyme.
3 In a medium bowl whisk together eggs, sour cream, and water. Sprinkle the cheese into the pie crust. Top with the mushroom-kale mixture and pour the egg mixture on top. Reduce oven temperature to 350 degrees. Bake for 35 minutes or until knife inserted in the middle comes out clean. Let stand for 5 minutes before cutting into wedges and serving.