Heat oven to 350°. Bring a large pot of lightly salted water to boiling. Add campanelle and cook 8 minutes, or about 1 to 2 minutes less than package directions. Drain and set aside.
Meanwhile, in a large saucepan, heat 1 tablespoon of the butter and the oil over medium heat. Add shallots and cook 3 minutes. Stir in mushrooms and thyme; cook 5 to 7 minutes. Add garlic and cook another 1 to 2 minutes.
Add remaining 1 tablespoon butter to saucepan; when melted, sprinkle in flour, whisking for 2 minutes. Pour in milk, whisking until liquid comes to a boil. Simmer until thickened, about 3 minutes. Remove from heat and stir in cheese, salt and pepper until smooth. Stir in cooked campanelle.
Pour mixture into a 13 x 9 x 2-inch baking dish. Bake at 350° for 20 minutes, until lightly browned and bubbly.