Preheat oven to 400 degrees F, grease a baking sheet, set aside.
In a shallow dish combine flour with salt, pepper, garlic powder, and chili powder, stir to combine. In a medium mixing bowl combine the milk and the egg, whisk to combine. In another shallow dish combine the panko breadcrumbs and the parsley, stir to combine.
Clean the mushrooms and pat dry, leave any stems on. Take each mushroom and dip in in the milk mixture, than coat in the seasoned flour, dip the mushrooms again into the milk mixture than coat one more time in the seasoned panko mixture.
Coat all mushrooms the same way, milk, flour, milk, panko. Lay out in a single layer on the baking sheet and bake for 15-20 minutes, until golden brown. Serve with your favorite sauce.