Peel and slice the Vidalia onions.
In a large skillet, melt the butter over medium heat.
Add the onions to the skillet and sauté until golden brown and caramelized, about 25-30 minutes.
Season the onions with salt, garlic powder, and oregano while sautéing.
Preheat the oven to 375°F (190°C).
Transfer the caramelized onions to a baking dish.
In a bowl, combine the Italian blend cheese, cheddar cheese, and parmesan cheese.
Sprinkle the cheese mixture evenly over the caramelized onions.
Bake in the preheated oven for 10-15 minutes, or until the cheese is melted and bubbly.
Serve hot and enjoy!
