Heat a large skillet over medium-high heat with oil.
Add sweet Italian sausage and break it up into small pieces with a wooden spoon or a potato masher.
Cook until the sausage has browned and is cooked through; about 5-6 minutes.
In a mixing bowl, add eggs, milk, salt, and pepper. Whisk to combine.
Pour the eggs over the sausage and reduce the heat to medium. Scramble until the eggs are dry. Remove from heat and reserve.
On a floured surface, roll out pizza dough until it is rectangle measuring about 16 inches by 10 inches.
Cut the dough into 4 equal strips, making each piece of dough 4 inches wide.
Evenly distribute the shredded mozzarella into the bottom of each pizza dough strip.
Evenly distribute the scrambled egg mixture on top of each mound of cheese and seal each dough by folding and pressing the corners in so that nothing leaks out.
Preheat a waffle iron to medium heat.
Spray with cooking spray and place each pizza dough piece into the waffle iron and cook until browned and crispy on the outside, about 8 minutes.
Remove and serve with warmed marinara sauce.
*If packing for lunch, let the sandwiches cool, slice them in half and pack them up with marinara sauce on the side.