Place unbaked pie crust in deep dish pie plate; flute edges if desired. Cover and refrigerate for at least 30 minutes and up to 3 days.
When you're ready to bake, preheat oven to 375 °F (191 °C). Line pie crust with parchment paper or foil and fill with pie weights or dried beans. Bake 12 minutes. Remove parchment paper and weights and prick bottom and sides of crust all over with a fork. Return to oven and bake 8 minutes more. Remove and set aside; leave oven on.
Meanwhile, cook bacon in a large skillet over medium heat until bacon is crisp; pour off all but 1 tablespoon of fat. Add asparagus; cook and stir 2-3 minutes, until bright green and crisp-tender. Remove from heat and set aside to cool.
In a large bowl, whisk together cream, milk, eggs, salt, pepper and thyme until smooth. Stir in green onions, cheese and asparagus and bacon mixture.
Pour egg mixture into partially baked pie crust and bake 40 minutes, or until the center is just set (cover pie crust edges with foil or a pie crust shield in the last 15 to 20 minutes of baking if crust is getting too brown). Let stand at least 15 minutes before cutting. Serve quiche warm or at room temperature.
Notes
To reheat leftover quiche from the refrigerator; cover with foil and warm in a preheated 350˚F oven for 15 to 20 minutes. To reheat frozen quiche (do not thaw before reheating), follow the same directions, but increase the reheating time to 30 to 45 minutes or when the internal temperature reaches 160˚F to 165˚F.