01 - Preheat oven to 375°F. Lightly grease a 2.5-quart baking dish.
02 - Bring a large pot of salted water to a boil. Cook macaroni 2 minutes less than package instructions. Add broccoli florets during the last 2 minutes. Drain and set aside.
03 - In a medium saucepan over medium heat, melt butter. Whisk in flour and cook 1 to 2 minutes until lightly golden.
04 - Slowly whisk in milk and continue cooking, whisking constantly, until thickened about 5 minutes. Remove from heat and stir in cheddar, Gruyère, Dijon mustard, garlic powder, onion powder, nutmeg, salt, and pepper until sauce is smooth and cheese is melted.
05 - Mix cooked macaroni and broccoli into the cheese sauce until evenly coated. Transfer to prepared baking dish.
06 - In a small bowl, combine panko, Parmesan, and olive oil. Sprinkle evenly over the pasta mixture.
07 - Bake for 20 to 25 minutes until bubbling and golden brown on top. Let rest for 5 minutes before serving.