Prep the Mushrooms: Clean and remove the stems from the mushrooms, leaving the caps whole.
Coat the Mushrooms: In a bowl, mix flour, breadcrumbs, garlic powder, paprika, salt, and pepper. In another bowl, whisk the egg and milk together.
Fry the Mushrooms: Dip each mushroom cap into the egg mixture, then coat with the flour mixture. Heat oil in a pan over medium heat and fry the mushrooms until golden and crispy (about 2-3 minutes per side). Drain on paper towels.
Prepare the Sliders: Toast the slider buns lightly. Mix mayonnaise and sriracha for a spicy sauce.
Assemble the Sliders: Spread the sauce on the bottom half of each bun. Layer with lettuce, a fried mushroom, and a slice of tomato. Top with the other half of the bun.
Serve: Serve immediately and enjoy your crispy, savory sliders!