Preheat your oven to 375°F (190°C). Prepare a baking dish by lightly greasing it or lining it with parchment paper for easy cleanup.
Peel and slice the sweet onions into rings about ¼ inch thick, separating the rings gently to allow even cooking.
In a large bowl, toss the onion rings with the melted butter, ensuring each ring is coated evenly.
Arrange the buttered onion rings in the baking dish in a single layer or overlapping slightly.
Sprinkle salt and pepper generously over the onions to taste.
Evenly distribute the grated cheddar cheese over the onion rings, covering them completely for maximum flavor.
Top the cheese layer with the breadcrumbs, spreading them evenly to create a crunchy topping.
Bake the onions in the preheated oven for about 20-25 minutes or until the cheese is melted and bubbly and the breadcrumbs turn a golden brown.
Remove from the oven and let cool slightly before serving.
