Preheat the oven to 375 degrees F (190 degrees C).

Cook bacon in a large, deep skillet over medium-high heat, turning occasionally, until evenly brown. Drain on paper towels. Crumble and set aside.

Meanwhile, cook spinach according to package instructions. Allow to cool, then squeeze dry.

Heat olive oil in the skillet over medium heat. Sauté onion until soft and translucent. Stir in mushrooms; cook until soft, about 2 minutes. Stir in ham and bacon. Remove from heat.

Combine sour cream and spinach; season with salt and pepper. Divide evenly between crusts, then divide and arrange bacon mixture on top. Combine Monterey Jack, Cheddar, and Parmesan; divide and sprinkle over bacon mixture.

Whisk eggs, half-and-half, and parsley together in a separate bowl; season with salt and pepper. Divide and pour into crusts.

Arrange quiche on a baking sheet; bake in the preheated oven on middle shelf until tops puffed and golden brown, 40 minutes. Remove from oven; let stand 5 to 10 minutes.