Cut off stems of cauliflower and steam florets until tender.
Place in a food processor and add butter, salt, pepper and garlic powder.
Process until smooth, no lumps.
Preheat oven to 350 degrees F.
Cook pancetta in a saute pan over medium high heat until crisp. Drain on paper towel.
Place pureed cauliflower in a bowl and stir in half of each kind of cheese. Save remaining cheese for topping.
Stir in pancetta, save some pieces for topping.
Stir in scallions and save some to sprinkle on top when serving.
Grease pan with olive oil cooking spray.
Spread mixture evenly into dish.
Sprinkle the rest of the cheese over the top of the mixture.
Bake for 30 minutes or until bubbling on the edges.
Allow to cool for 15 minutes before serving.
Sprinkle with extra pancetta and scallions before serving.