Preheat the oven to 400 F. In a shallow dish, whisk egg and milk together. Place flour into another shallow dish. In another shallow dish, combine cornmeal and breadcrumbs.
Fully coat each green tomato slice in the egg mixture, then coat in the flour, coat back into the egg mixture, then coat in the cornmeal and breadcrumb mixture.
Place onto a large greased baking sheet. Bake for 20-25 minutes.