Calzones will never be the same: This giant, doughy football has a meatball surprise inside.
Position the oven racks in the upper and lower thirds of the oven and preheat to 350°F. Line two baking sheets with parchment.
Whisk together the garlic, milk, parsley, Parmesan, crushed red pepper, 2 eggs, 1 1/2 teaspoons salt and a few grinds of black pepper in a large bowl. Add the beef and use your hands to mix everything together until well combined.
Drop heaping tablespoons of the meat mixture onto the prepared baking sheets (you should have about 40 mounds). Use slightly damp hands to roll the mounds into balls. Bake until just browned and almost cooked through, about 20 minutes.
Bring the marinara to a simmer in a large saucepan over medium-high heat. Add the meatballs, bring back to a simmer, and cook, stirring occasionally, until the meatballs are just cooked through, 7 to 8 minutes.
Discard the parchment from the baking sheets and wipe one baking sheet clean. Coat the back of the baking sheet with nonstick cooking spray. Using your hands, spread one package of dough into a 15-by-12-inch rectangle on the baking sheet (it should be about the size of the baking sheet). Draw the outline of a football shape in the dough, about 1- inches-wide and 15-inches-long. Spoon half of the meatballs, tapping off any excess sauce, inside of the football outline on top of the dough. Sprinkle with 1 cup of mozzarella. Repeat with the remaining meatballs and remaining 1 cup mozzarella.
On a lightly greased surface, spread the remaining package of dough into a rectangle big enough to cover the meatballs. Place the dough on top of the meatballs and press the dough together around the meatballs. Cut out the football shape leaving a 1-inch border around the edges, reserve the scraps. Tuck and tightly secure the edges underneath the dough to prevent any cheese from leaking out.
Beat the remaining egg with 1 tablespoon water in a small bowl. Brush the top of the football with the egg wash. Pour the sesame seeds onto a plate.
Using the scraps, roll out two 12-inch-long ropes to make the lines for the football. Gently roll the strips in the sesame seeds to coat. Press the ropes on the sides of the football, widthwise, so they are about 9-inches apart. Roll out one 9-inch-long rope and then roll in the sesame seeds. Place the rope lengthwise in between the two widthwise ropes. Roll out three 3-inch-long ropes then roll them in the sesame seeds. Place the ropes equidistance apart on top of the 9-inch rope.
Mix the butter with the garlic salt and brush the entire football. Bake until the dough is a deep golden brown and completely cooked through, 55 to 60 minutes. Let cool for 10 minutes and serve with the remaining marinara sauce.