Preheat the oven to 400 degrees Fahrenheit (200 degrees Celsius) and line a baking sheet with parchment paper.
Clean the mushrooms with a damp paper towel and carefully remove the stems to create a cavity for the filling.
In a medium mixing bowl, combine the blended cottage cheese, Greek yogurt, and parmesan cheese until smooth.
Fold in the squeezed dry spinach, garlic powder, onion powder, salt, and black pepper.
Stir in 1/4 cup of the shredded mozzarella cheese into the mixture.
Spoon the spinach protein mixture evenly into each mushroom cap, pressing down slightly.
Arrange the mushrooms on the prepared baking sheet and top each with the remaining mozzarella cheese.
Bake for 18 to 20 minutes until the mushrooms are tender and the cheese topping is golden and bubbly.
Allow the mushrooms to rest for 5 minutes before serving to ensure the filling sets.