Let's not call this mac 'n cheese, because it has no mac. Quinoa stands in here, but really it is a dish all unto itself. It's full of flavor, great as a side, and any veg head would be very happy making this their main course, along with a salad or two. It is trying to be healthy, with olive oil replacing the butter in the bechamel, and can be made gluten free by subbing gluten-free flour in the bechamel and gluten-free bread crumbs for the topping.
Heat 3 tablespoons of the oil in a large saucepan over medium heat. Add the onion and cook for 5 to 6 minutes, until translucent. Add the flour and cook, stirring, for 2 to 3 minutes. Pour in the milk in a slow stream, whisking continuously. Cook, stirring frequently, until the mixture comes to a boil. Lower the heat and simmer for 6 to 8 minutes, until thickened. Add 8 ounces of the cheddar cheese, whisking until fully melted. Turn off the heat, stir in the salt, pepper, and nutmeg to taste, the cayenne, and the mustard powder. Transfer to a large bowl, add the quinoa and kale, and mix well.
In a small bowl, stir the remaining 1 tablespoon oil with the panko. Mix in the Parmigiano-Reggiano and set aside. Butter a 10-inch cast-iron skillet or similar size baking dish. Transfer the quinoa mixture to the skillet and scatter the panko topping over it. Top with the remaining cheddar cheese. Bake uncovered for 40 to 45 minutes (or up to 55 minutes if taken from the fridge), until golden brown and bubbling at the edges. Serve immediately.
Note: I called for cooked quinoa in this recipe, because the volume can vary depending on what color you use and how it is being cooked. I usually cook 1 1/2 cups dry with 2 3/4 cups water, rice style, for 15 minutes, covered, which will yield a bit (about 1 1/2 cups) more than what's needed for this recipe. Use the extra in a salad or grain bowl.
- Up to 2 days ahead, make the bechamel, shred the kale, and cook the quinoa.
- Up to 1 day a head: Assemble the dish; keep refrigerated.
- Just before serving: Bake the dish.