Soak wooden skewers in water for 10 minutes to help prevent scorching.
Heat oil in a deep, heavy pot to 350°F. Keep a baking rack over a sheet pan ready.
Combine Italian breadcrumbs, panko, Parmesan, garlic powder, Italian seasoning, salt, and pepper in a shallow dish.
Put flour in one shallow bowl and buttermilk in another to create a breading station.
Blot any surface ice from frozen ravioli. Thread 3–4 ravioli onto each soaked skewer.
Dredge each skewer in flour, dip in buttermilk, then press into the breadcrumb mixture to coat well.
Fry skewers in batches until deep golden and crisp, about 2–3 minutes. Turn as needed for even color.
Drain on the rack. Warm marinara. Sprinkle with parsley and serve hot with the sauce.