Preheat the oven to 375 degrees F. Coat 2 baking dishes with the butter.
Place chopped bacon on a baking sheet and cook in oven until half cooked, about 10 minutes. Drain off excess grease, reserve bacon.
In a large pot of boiling, salted water, cook elbow macaroni until al dente, about 8 to 10 minutes. Strain, toss lightly in olive oil, reserve.
In a saucepan, on medium-high heat, saute bacon with a light amount of olive oil. Add the onion and cook until translucent then add the garlic. Dust with flour, whisk in milk, cream, nutmeg, and mustard powder. Bring to simmer stirring constantly for several minutes. Whisk in 4 cups of Cheddar and half a cup of Parmesan. Stir until all the cheese is melted. Adjust the seasoning with salt, pepper and lemon juice. Fold in the pasta, sage and parsley.
Place into buttered baking dishes. Top with remaining cheeses and place dishes on baking tray and place in the oven. Bake until golden brown, about 20 to 25 minutes. Let cool about 5 minutes, garnish with parsley and sage leaves and serve!
Recipe courtesy of Derek Wagner, Providence, Rhode Island, 2007