Preheat oven to 375°.

Spray your pie dish with a small amount of nonstick cooking spray. Roll your pie crust into your pie plate.

Line your pie crust with a sheet of parchment paper and fill with pie weights. If you don't have pie weights, fill the crust with uncooked rice or dried beans.

Bake crust for 20 minutes and then remove from the oven to cool completely.

In a medium sauce pan, melt butter over medium high heat. Once the butter is shimmering, add the sliced mushrooms and sauté, stirring frequently, until most of the moisture has absorbed from the pan.

Add the chopped thyme, and ⅛ tsp salt and pepper to the mushrooms. Continue to sauté for an additional minute or two. Remove from heat and allow to cool.

In a large measuring cup, whisk eggs, 1 cup whole milk, and ¼ tsp salt and pepper. Whisk to combine.

Grate the gruyere directly into the bottom of the prepared crust. Leave ¼ (1.5 oz) of the block of cheese for sprinkling over the top of the quiche.

Arrange the cooked mushrooms over the cheese in a nice, even layer.

Pour the custard mixture over the mushrooms.

Sprinkle with remaining gruyere.

Transfer pie plate to a baking tray lined with a piece of parchment paper (to avoid and overflow from leaking all over your oven).

Bake at 375° for 35-45 minutes or until the center of the quiche wiggles (like Jello) just a little when you shake the pan. If you notice that the edges of your crust are getting to cover with a pie crust shield or aluminum foil.

Remove the quiche from the oven and allow to rest for 20-30 minutes. Cut quiche into wedges and serve alongside your favorite salad.