Separate the onion rings, then place a small ring inside a large ring on a cutting board or clean work surface.

Fill the gaps between the rings with strips of provolone cheese. The cheese should fit snugly between each onion ring so that it holds the rings together and keeps them from falling apart. Refrigerate until ready to use.

Pour enough oil into a large heavy-bottom pot or Dutch oven to reach 2 inches up the sides. Attach a deep-fry thermometer and place over medium heat. Bring to 350 degrees F.

Place the panko in a shallow baking dish and stir in 2 teaspoons of the all-purpose seasoning until evenly combined.

Place the flour, 2 teaspoons of the all-purpose seasoning, ½ teaspoon of salt and several grinds of black pepper in another shallow baking dish and whisk to combine.

Place the eggs, buttermilk, remaining 2 teaspoons all-purpose seasoning, ½ teaspoon of salt and several grinds of black pepper in a third shallow baking dish and whisk to combine.

Dip one cheese-filled onion ring in the flour mixture, then in the egg mixture, letting the excess egg drip off. Then dip the onion ring back into the flour mixture, then back into the egg mixture. Finally place it in the panko mixture, very gently tossing until it’s evenly and well coated.

Transfer to a baking sheet and repeat until all the rings are coated.

Working in batches, carefully place the onion rings into the hot oil.

Fry until golden brown and crisp, 2 to 3 minutes. Remove with a slotted spoon and drain on a plate lined with paper towels. Sprinkle with salt while still warm. Serve warm with warmed marinara sauce for dipping.