#1. Preheat oven to 375°F. Grease 1 ½-quart baking dish with 1 tablespoon butter and set aside. #2. Melt 3 tablespoons butter. In a mixing bowl, stir together melted butter with breadcrumbs. Set aside. #3. Bring a large pot of salted water to a boil. Add macaroni and cook until al dente. #4. While pasta is cooking, melt remaining 2 tablespoons butter over medium heat in a medium saucepot. Whisk in flour and stir constantly for 2 minutes. Slowly add milk, whisking constantly to avoid lumps. Continue to cook until mixture is thick, 2-3 minutes. Turn off heat and stir in nutmeg and pepper. Add cheese and stir to melt. #5. Drain cooked pasta and stir into cheese sauce. Fold in yogurt until evenly combined. Transfer to prepared baking dish and top evenly with breadcrumbs. Bake for 15-20 minutes, or until golden brown.