Preheat the oven.

Caramelize the sliced onions in a pan.

In a bowl, combine the cream cheese, heavy cream, garlic powder, salt, and black pepper.

Mix in the caramelized onions and 1 cup of shredded cheddar cheese.

Pour the mixture into a baking dish.

In another bowl, mix the breadcrumbs with melted butter and the remaining cheddar cheese.

Sprinkle the breadcrumb mixture on top of the onion mixture.

Bake in the preheated oven until golden brown and bubbly.