Preheat oven to 400 degrees. Line a 9 x 13 inch cake pan with a silicone baking mat or parchment paper. Set aside. Grind the psyllium husk until it's about half its volume. Pour the ground husk into a large mixing bowl. Sift the dry ingredients into the bowl with the psyllium husk until there are no lumps
Stir all the wet ingredients in except the cheese and water until fully combined. Gradually fold the cheese into the mixture until evenly distributed. Stir in the hot water until combined. Keep stirring for 1 minute until a smooth dough has formed.
Form the dough into a ball and knead the dough in the bowl for 1 minute until smooth and flexible. Form the dough back into a ball and place in the center of the prepared cake pan. Press the dough evenly throughout the pan.
Bake in the preheated oven for 5 minutes to firm the crust. Remove Spread up to 1 1/2 cups of cheese evenly over the top of the firm crust. Cut the cheese sticks into small chunks and place around the edges of the crust. Spread the sauce evenly over the top of the cheese on the crust. Spread the pepperoni evenly over the sauce.
Bake in the preheated oven for 10 to 15 minutes or until the cheese on the edges is very brown. Remove from the oven and let cool for 5 minutes before slicing into desired size slices.