Preheat oven to 200°C (400°F) and line a baking tray with parchment paper.
Slice onions into rings and separate them carefully.
Prepare three bowls: flour in one, beaten eggs with milk in another, and breadcrumbs mixed with spices in the third.
Dip each onion ring into flour, then egg mixture, then coat with breadcrumbs.
Place coated rings on the prepared baking tray in a single layer.
Lightly brush or spray with olive oil for crispiness.
Bake in the preheated oven for 18–20 minutes until golden and crispy.
Flip halfway through baking for even crisping.
Remove from oven and let cool slightly before serving.