1. Place the spinach on a plate and microwave it for 6 minutes on high to defrost it. Place it in a clean kitchen towel and wring it dry, then reserve.

2. While the spinach is defrosting, get a large pot of water on the stove for the pasta. Bring to a boil, then salt the water liberally and cook the pasta until al dente.

3. While the pasta cooks, heat a deep, large skillet over medium heat. Add the EVOO, then melt the butter into the oil. When the butter melts, add the onions and garlic and cook until tender, 4-5 minutes. Sprinkle the flour around the pan and cook for a minute,t hen whisk in the wine.

4. Whisk in the stock, then whisk in the milk and bring it to a bubble. Reduce the heat a bit.

5. Season the sauce with the nutmeg, hot sauce, and mustard, then season with salt and pepper to taste. Simmer for 2-3 minutes to thicken, then add the spinach, separating it as you add it to the sauce.

6. Preheat the broiler.

7. Back to the sauce, add the tuna, flaking it as you go, then stir to combine. Heat the spinach and tuna through for a minute or so.

8. Drain the pasta and toss with the sauce.

9. Transfer the tuna to a casserole dish and cover it with the Parm or Romano. Place the casserole under the broiler for 2 minutes to brown the edges and the cheese. Top with the parsley and serve.