Cook rotini according to package directions.
Lightly steam kale until tender, then drain.
In a large skillet on medium heat, add butter and 2 tablespoons of olive oil. Add onions and cook until they become translucent; add garlic and oyster mushrooms and cook until tender, about 10 minutes, stirring frequently.
Combine cooked ingredients on a serving platter; add remaining tablespoon of olive oil and salt and pepper to taste. Sprinkle Parmesan cheese on top and serve.