"This is a recipe some coworkers of mine made for an outdoor Dutch oven cooking competition about 20 years ago and I've adapted to a conventional oven. My wife loves this and we've even had it as a main course although it is better suited to a side dish due to its rich flavor."
Melt butter in a Dutch oven over medium-low heat. Mix onion, brown and wild rice mix, and water in the melted butter. Layer tomatoes over rice mixture; top with zucchini. Cover zucchini with Colby cheese.
Mix sour cream, garlic, salt, Italian seasoning, red pepper flakes, and black pepper together in a bowl; spread over Colby cheese layer. Cover Dutch oven.
Bake in the preheated oven until rice is tender and cheese is bubbling, about 45 minutes.