Ingredients:
3 sweet onions, sliced into 1/4-inch slices
1 1/2 tsp. cajun seasoning, or more to taste
1 tsp. garlic powder
4 tbsp. butter, cut into 6 slices
1 cup shredded cheddar cheese
1 cup shredded mozzarella cheese
1/2 tsp. dried oregano
1/2 cup grated parmesan cheese
Instructions:
Preheat the oven to 350 degrees F.
Arrange 1/2 of the onions on the bottom of a 9x13-inch casserole dish. Sprinkle with half the Cajun seasoning and half the garlic powder. Repeat with remaining onions, seasoning, and garlic powder.
Arrange butter on top of the onions and top evenly with Cheddar and mozzarella cheese. Sprinkle oregano over cheese and top with Parmesan cheese.
Bake in the preheated oven until onions are tender and cheese is melted, bubbly, and golden brown around the edges, about 35 minutes.