
Preheat the Oven: Set your oven to 400°F (200°C) and line a baking sheet with parchment paper. Lightly grease it with olive oil to prevent sticking.
Prepare the Coatings: In a large bowl, mix the flour, salt, and pepper. In another bowl, whisk together the eggs and milk until smooth.
Coat the Onions: Dip each onion slice first into the flour mixture, then into the egg mixture, and finally coat with a mixture of breadcrumbs, shredded cheddar cheese, and grated Parmesan.
Bake: Arrange the coated onion slices on the prepared baking sheet in a single layer. Drizzle with a little more olive oil for extra crispiness. Bake for 20-25 minutes, or until the crisps are golden brown and crunchy.
Garnish and Serve: Remove from the oven and sprinkle with chopped fresh parsley for a festive touch. Serve hot and enjoy the cheesy, savory goodness.