Preheat the oven to 375°F. Butter an 8x8-inch baking dish and set aside.
Cook pasta in a large pot of boiling, salted water until al dente. Drain and set aside.
In a medium skillet, melt 2 tablespoons butter. Add the bread crumbs and 1 cup of the Barely Buzzed Cheddar. Mix well, transfer to a bowl, and set aside. Wipe out but do not wash skillet.
In the same skillet, melt 2 tablespoons of butter over medium heat. Add the mushrooms and cook until softened. Season to taste with salt and pepper and set aside.
In a small sauce pot, heat the 1/2 cup of milk, 1/2 cup of cream, garlic, parsnips, and the remaining tablespoon of butter. Cover and cook over low heat, stirring occasionally and watching to make sure the cream mixture does not boil. Simmer the parsnips until they are soft (about 15 to 20 minutes).
Cool slightly, the place in a blender or food processor and purée. Put the purée back into a pot with the remaining cup of milk, 1 cup cream, and 1 teaspoon salt. Cook until slightly thickened and warmed through.
Remove from heat and add the smoked mozzarella and the remaining Cheddar, and stir until the sauce is smooth.
Mix the sauce, mushrooms, and pasta together. Pour into prepared pan and bake until golden brown and bubbly, about 20 to 30 minutes.