Preheat oven to 400°F.
You can either make your own crust here or buy a ready-made one from the grocery store. I used a gluten free ready-made one but you use what suits you best. Pre-bake it by putting a piece of foil or parchment over it, weighting down with dried beans, and into the oven for 10 minutes. Remove weights and foil or parchment and bake 5 more minutes. Cool and reduce oven temperature to 375°F.
Heat a skillet on high, add in butter, then mushrooms and sauté until browned, about 5 minutes. Set aside.
Chop turkey bacon into small pieces and add to the same skillet. Cook until browned, about 5 minutes. Set aside.
In a large bowl, whisk together eggs, milk, chives, garlic powder, salt, and pepper. I like a slightly less custardy quiche so use a higher egg to milk ratio than is standard.
Assemble the quiche. Pour the egg mixture into the crust. Then add in the mushrooms and bacon.
Transfer to oven and bake until center is ever so slightly jiggly, about 45 minutes. Let cool, then slice.