Wipe mushrooms with a damp paper towel and pop out stems so the caps are ready for breading.

Set up three bowls: Bowl 1 with flour, Bowl 2 with beaten eggs mixed with milk, and Bowl 3 with breadcrumbs combined with garlic powder, onion powder, salt, and pepper.

Shake off excess flour first, then dip each mushroom into the egg mixture to help the crumbs stick.

Finally coat each mushroom in the breadcrumb mix, pressing crumbs onto the surface so they form a firm crust.

Pour vegetable oil into a deep pan about 1/2 inch deep and heat over medium until shimmering but not smoking.

Fry mushrooms in batches until golden and crispy, about 3–4 minutes per batch, turning if needed for even color.

Remove mushrooms to paper towels to drain, serve hot, and offer ranch dressing for dipping.