Remove the stems from the portobello mushrooms. Use a spoon to scrape out the dark gills and discard them. Slice the mushrooms into 1/4-inch thick strips.

Set up a breading station with three shallow dishes: one with flour, one with beaten eggs, and one with panko breadcrumbs mixed with steak seasoning.

Dredge each mushroom slice in flour, then dip into the egg, and finally coat well in the seasoned breadcrumbs.

Arrange the breaded mushroom slices in a single layer on the baking sheet. Lightly spray with non-stick cooking spray.

Bake for 8–10 minutes, flipping once halfway through, until the mushroom fries are golden brown and crispy.

Serve immediately with ketchup or your favorite dipping sauce.