Add almond flour, coconut flour, xanthan gum and salt to food processor and pulse to combine. With the motor running, add the apple cider vinegar, egg and water, a tablespoon at a time, until the dough forms into a ball.
Fry the pancetta in a large heavy-bottomed skillet. Transfer to a plate and set aside. Add the butter to the same skillet and melt over medium heat. Add the garlic and cook for 30 seconds. Add the pasta and cook for 3-5 minutes or until it just begins to get some color. Add the pancetta and toss to combine.