Preheat oven to 400°. Add panko, Parmesan, and Italian seasoning to a large bowl. Season with salt and pepper, then mix everything together until thoroughly combined.
Dip cauliflower pieces in egg and then roll in bread crumb mixture until fully coated and place on a baking sheet lined with parchment paper. You may need to press on the coating to help it stick to the cauliflower bites. Repeat until all cauliflower florets are coated.
Bake for 20 to 25 minutes, until coating is golden brown and crunchy. Serve with marinara.