Place mozzarella cheese and cream cheese in a large microwave safe bowl. Heat the cheeses together in microwave on high for 30-60 seconds. Remove the bowl from the microwave and stir. Continue to repeat the microwave heating until all the cheese is completely melted and combined.
Next, add the room temperature egg to the melted cheese and stir with a rubber spatula until fully mixed. Add in the almond flour, baking powder and psyllium husk (or oat fiber), then continue to knead the dough mixture until fully combined and resembles a ball of dough.
Lay out a large baking sheet lined with parchment paper. Place the ball of dough in the middle of the baking sheet. Place another sheet of parchment paper over the dough. Press the dough out into a large rectangle using your hands or a rolling pin.
The rectangle of dough should be 12-14” long and 10” wide. Remove the top sheet of parchment paper. Think of your long dough rectangle in 1/3 sections. The long center 1/3 will be where you place your ham and cheese layers.
Keep the long center 1/3 of the dough empty and slice the long outer 1/3 on each side of the dough into diagonal strips strips. Set aside.
Assemble
Brush or smooth on 2 tbsp dijon mustard in the CENTER of the dough running the length of the dough. Leave 3-4” of dough on each side of the smeared dijon mustard.
ALternating ham and cheese, layer the slices on the center of the dough over the mustard. Then spread the last 2 tbsp of dijon mustard over the ham and cheese.
Starting at the side bottom of the dough alternate wrapping the diagonal strips of the dough over the ham and cheese layers. Press and form the dough decoratively over the filing.
Once the sides are covering the top of the dough, press and seal the dough over the ham and cheese to form the stromboli.
Egg Wash
Using a fork, whisk an egg for the egg wash. Using a pastry brush, wash the stromboli dough completely with the egg wash. You may not use the complete egg. OPTIONAL....Sprinkle the stromboli with poppy seeds or sesame seeds if you wish.
Bake
Place stromboli in the oven for 30 mins at 350*. At the end of your baking time you may wish to turn your oven to broil to brown the top of your stromboli for just a minute or 2.
Let the Ham and Cheese Stromboli cool a bit before you slice and serve. Enjoy.
Notes
If you are using thin sliced ham and cheese you will probably need to do two layers of the alternating ham and cheese.