Prepare the Mushrooms: Clean and pat the mushrooms dry. Keep them whole or slice larger ones in half.
Set Up Coating Stations: Place flour in one bowl, beaten eggs in another, and mix panko breadcrumbs, paprika, garlic powder, salt, and black pepper in a third.
Coat the Mushrooms: Dip each mushroom into the flour, shaking off excess. Next, dip it into the beaten egg, and finally coat it thoroughly in the breadcrumb mixture.
Heat the Oil: Heat vegetable oil in a deep frying pan to 350°F (175°C).
Fry the Mushrooms: Fry the coated mushrooms in batches for 2–3 minutes or until golden brown. Remove and drain on paper towels.
Prepare the Sriracha Mayo: In a small bowl, whisk together mayonnaise, Sriracha, and lemon juice until smooth. Adjust Sriracha to taste for more or less spice.
Serve: Serve the golden mushrooms warm with the Sriracha mayo on the side for dipping.