Add almond flour, coconut flour, salt, xanthan gum and vinegar to the food processor. Pulse a few times, then add cold oil. Keep pulsating until the dough looks like bread crumbs. Add the egg and pulsate again. The dough will form into a ball. Wrap with plastic wrap and refrigerate for 45-60 minutes.
Lubricate the baking dish with butter, put the dough in the mold and mash it with your fingers along the bottom and edges. Put half the cheese and pepperoni on the base. Mix eggs, cream, Provencal herbs and salt. Pour the mixture into a mold, put on top the remaining cheese and pepperoni.
Cover with foil and bake for about 35-45 minutes. in an oven preheated to 180 ° C. Remove the foil and continue to bake for another 10-15 minutes.