Place racks in center and lower third of oven; preheat to 300°. Fill a 13" x 9" metal pan with ½" water and place on lower rack.

Place bacon in a cold, large skillet. Cook over medium heat, stirring occasionally, until browned and crisp, about 10 minutes. Transfer bacon to a paper towel-lined plate and let cool.

In a blender, combine eggs, Gruyère, cottage cheese, cornstarch, butter, hot sauce, and vinegar; season with salt and pepper. Blend on high speed until smooth and fluffy, about 30 seconds.

Spray a standard 12-cup muffin tin with cooking spray. Fill each well about two-thirds full with egg mixture. Top each with bacon. Using a toothpick, submerge some bacon pieces.

Bake egg bites on center rack until eggs start to pull away from sides of pan, 20 to 24 minutes. Let cool slightly.

Using an offset spatula, transfer egg bites to a platter.

In a large skillet over medium heat, melt butter. Add mushrooms and cook, stirring occasionally, until browned, about 5 minutes. Add kale; season with salt. Cook, stirring occasionally, until kale has started to wilt and soften, 3 to 4 minutes. Add garlic and parsley and cook, stirring, until fragrant, about 1 minute more. Transfer to a plate and let cool.

In a blender, combine eggs, cottage cheese, Monterey Jack cheese, Swiss cheese, cornstarch, hot sauce, and vinegar; season with salt and pepper. Blend on high speed until smooth and fluffy, about 30 seconds. Add kale mixture and blend until well combined, about 10 seconds more.

Spray a standard 12-cup muffin tin with cooking spray. Fill each well about three-quarters full with egg mixture.

Bake egg bites on center rack until eggs start to pull away from sides of pan, 20 to 24 minutes. Let cool slightly. Using an offset spatula, transfer egg bites to a platter.