1.Cook the macaroni for about 4 minutes to al dente, according to package instructions. Drain and set aside. Shred cheeses and set aside. Preheat oven to 325 degrees F.
2.In a small pan add olive oil on medium heat, once warmed add shallot and garlic then quickly stir and add all the mushrooms plus thyme. Cook until softened, season with salt and pepper. Pick out the thyme sprigs and discard. Mix with the macaroni.
3.Melt 4 tablespoons butter in a medium saucepan over medium heat. Blend in the flour, garlic powder, 1 teaspoon salt, and 1/2 teaspoon pepper. Cook for 2 minutes.
4.Slowly add the milk and half and half, stirring constantly and bring to a simmer and simmer 1 minute. Remove from heat and stir in 1 tablespoon truffle oil, and then shredded cheddar and gruyere cheeses, stirring just until melted.
5.Add the cooked macaroni noodles and toss to coat. Pour half or the pasta mixture into a greased 9×13 baking dish. Sprinkle ¼ cup parmesan cheese over the top. Add remaining pasta and sprinkle with remaining parmesan cheese.
6.Add panko, 2 tablespoons butter and 1 tablespoon truffle oil to a skillet. Cook over medium-high heat, stirring constantly, until the crumbs are golden brown. Evenly sprinkle over the mac cheese.
7.Bake 15-20 minutes or until bubbly. Serve warm.