Preheat the oven to 350°F.

Bring a pot of salted water to a boil. Add the pasta and cook for 4 minutes less than the package directions, then add the broccoli and boil for 3 more minutes. Drain in a colander and run under cold water to stop the cooking. The pasta should still be al dente.

In a large skillet over medium heat, add the olive oil and kielbasa and sauté for 2-3 minutes until golden brown. Set aside.

Add the butter to the skillet. Once melted, add the flour and whisk into a paste. Cook for 1-2 minutes, until golden. Add 1 cup of the milk and whisk until incorporated, then add the remaining milk and continue whisking until the sauce is smooth with no lumps. Stir in the Dijon, salt, onion powder and garlic powder and gently simmer for about 5 minutes, until the sauce has thickened.

Remove from the heat and stir in the cheddar and mozzarella until smooth.

Add the pasta, broccoli and kielbasa to a large baking dish, pour the sauce over the top and stir until everything is well coated.

In a small bowl, toss the panko with the melted butter until evenly coated, then sprinkle over the pasta.

Bake for 20 minutes, until the sauce is bubbling. If the panko isn't golden brown yet, turn the oven to broil for 1-2 minutes, watching closely so it doesn't burn.