It is a bit difficult to find Tapioca Flour, but my local Asian Market carried it. I found the original recipe here, but have adapted it a bit for my tastes.
1/2 cup butter
1 cup whole milk
1/2 teaspoons garlic powder
2/3 cup freshly grated Romano Cheese
1/3 cup freshly grated Parmesan Cheese
Preheat oven to 375 degrees F (190 degrees C).