Preheat oven to 425 degrees. Spray 36 mini muffin tins well with gluten free non-stick cooking spray.
Cook the pasta in lots of heavily salted boiling water per the package directions. Drain and rinse with hot water.
In a small bowl, stir together 2 tablespoon of milk with the corn or tapioca starch.
In a large skillet, melt the butter over medium heat. Add the onion, salt, pepper and nutmeg and cook until the onions very soft but not browned, about 5 minutes.
Add the remaining ¾ cup of milk and bring to a boil. Stir in the corn starch mixture and boil until thickened, just a few seconds.
Stir in ¼ cup of parmesan cheese and the cheddar cheese. Lower heat and stir until the cheeses are melted.
Add the cooked pasta and stir to coat the pasta with the cheese sauce. Taste and add some more salt and pepper if needed.
Combine the remaining 2 tablespoons of parmesan cheese with the bread crumbs.
Spoon rounded tablespoons of the mac and cheese mixture into the prepared muffin tins, gently pressing down with the back of a spoon.
Sprinkle as pinch of the bread crumb mixture on top of each mac and cheese bite and bake for 11 – 12 minutes or until the bites are golden brown and sizzling. Let cool for 5 minutes then run a knife around each bite and remove from the pans. Serve warm.