Preheat oven to 350° F.
Dice onion and set aside.
Spray a 9-inch pie pan with cooking spray.
Heat a large skillet over medium-high; cook bacon until crispy, then crumble and add to bottom of pie plate. Sprinkle cheese on top.
Combine eggs, onion, spinach, salt, flour, and milk; whisk together until smooth, then pour over bacon and cheese.
Bake for 35 minutes or until set.
Meanwhile, slice tomato and dice peaches.
Top quiche with tomato slices if desired, or serve on the side.
Top peaches with yogurt and serve alongside quiche.