Ingredients
Preparation
- Cooking spray to prepare the pan
Main Ingredients
- 2 1/2 pounds Vidalia onions, cut into 1/2-inch slices (substitute Walla Walla or Maui onions if desired)
- 1 teaspoon dried thyme
- 1 teaspoon dried parsley
- 1 teaspoon garlic salt
- 1/2 teaspoon dried oregano
- 1/2 teaspoon dry mustard
- 1/4 teaspoon cayenne pepper (optional, can use up to 1/2 teaspoon for more heat)
- 1/4 cup salted butter, cut into pieces
- 4 ounces mild cheddar cheese, shredded
- 4 ounces smoked Gouda cheese, shredded
Instructions
- Preheat and Prepare: Preheat your oven to 350°F (175°C). Lightly coat a 9×13-inch baking dish with cooking spray to prevent sticking and ensure easy cleanup.
- Mix Spices: In a shallow bowl, combine the dried thyme, parsley, garlic salt, oregano, dry mustard, and cayenne pepper. Adjust cayenne to taste depending on your preferred level of heat or omit it completely for a milder dish.
- Layer the Onions: Arrange half of the sliced onions evenly across the base of the prepared baking dish. Evenly sprinkle half of the combined spice mixture over the onions.
- Add Butter and Cheese Layers: Scatter half of the butter pieces and half of the shredded cheddar and smoked Gouda cheeses over the seasoned onions layer.
- Repeat Layers: Repeat the layering process with the remaining onions, spices, butter, and cheeses to form a second layered casserole.
- Bake Covered: Cover the dish tightly with aluminum foil and bake for about 40 minutes. This allows the onions to soften and the sides to become bubbly.
- Finish Baking: Remove the foil and continue baking uncovered for an additional 15 to 30 minutes until the top turns golden and bubbly, developing a savory crust.
- Serving Suggestion: Serve warm alongside grilled steaks, barbecue dishes, burgers, or as a flavorful side to any Southern-style meal.
Notes
- Use a mandoline slicer to quickly achieve consistent 1/2-inch thick onion slices.
- For a crunchy topping, sprinkle breadcrumbs over the cheese after baking and broil briefly until golden.
- Try different cheese combinations like mozzarella, sharp cheddar, and parmesan for varied flavors.
- Make ahead by preparing the casserole up to 1 day in advance, cover, refrigerate, and bring to room temperature before baking for even cooking.
- Store leftovers in an airtight container in the refrigerator for up to 3 days. Avoid freezing as it affects texture.
- Prep Time: 10 minutes
- Cook Time: 55 minutes
- Category: Side Dish
- Method: Baking
- Cuisine: American
- Diet: Vegetarian
