Spray a rectangular baking dish with cooking spray. Combine the ham, turkey and cauliflower in the baking dish and set aside.
Melt 2 tablespoons of the butter in a medium saucepan. Add the shallots and cook for several minutes until the shallots begin to soften.
Whisk in the flour and cook for 2 minutes stirring frequently. Add the beer to the pan and continue to whisk until a smooth paste forms. Allow to cook for another 2 minutes.
Slowly whisk in the milk. Continue to cook, stirring constantly until the mixture comes to a boil. Reduce the heat to low.
Add the mustard, Worcestershire sauce, and hot sauce to the pan. Cook until the sauce thickens which should take several minutes.
Remove the pan from the heat and gradually stir in the cheddar cheese. Once everything is melted, pour the sauce over the meat and cauliflower mixture. Stir to combine.
Melt the remaining butter and toss with the bread crumbs. Sprinkle the crumbs evenly over the top of the casserole. Top with the Parmesan cheese and give the top a light blast of cooking spray.
Bake at 375 degrees for 25 minutes until everything is bubbly. Turn the oven to broil and let it go for 2 – 3 minutes until the top is golden brown.
Remove from the oven and allow to rest for 10 minutes before serving.