Cut mushrooms into ~1/2 inch wide strips. Don't worry about the pieces being uniform.
Prepare your coating. Take out 3 bowls. Add the panko breadcrumbs to one bowl. Next, add the flour, onion salt, black pepper, paprika, and garlic powder to the second bowl. Lastly, add the eggs to the third bowl and whisk.
Take a mushroom piece and dip it into the flour mixture, then the eggs, and lastly the panko. Repeat the process for all of the mushroom pieces.
Prepare a baking sheet by lining it with paper towels. Set aside.
Heat vegetable oil in a cast iron pan or dutch oven to 370 degrees F. Make sure the vegetable oil comes up 2 inches in the pan. Adjust the oil to the pan you are using.
Fry each mushroom for 30 seconds to 1 minute until the outside is golden and the inside is cooked. Fry in batches, so you don't crowd the pan. Once cooked, place mushroom fries onto the prepared baking sheet. The paper towels will drain excess oil.
Garnish with minced parsley, and serve with dip of choice. I chose to serve it with sriracha mayo and ketchup.