Prep: 1. Preheat oven to 450 and sprinkle a baking sheet with corn meal. 2. Slice mushrooms. Mince garlic. Make: 1. Heat 1 teaspoon of the olive oil in a large skillet over medium-high heat. Add the ground beef , 1/4 teaspoon salt, and a pinch of crushed red pepper. Break the beef into large chunks as it cooks for about 2 minutes. 2. When the beef is browned, add the mushrooms, garlic and 1/4 teaspoon salt. Cook for 3 minutes, then fold in the spinach to wilt, about 1 minute. Using a slotted spoon, remove to a large bowl to cool completely. 3. Reduce the heat to medium. Add the remaining olive oil, and a pinch of crushed red pepper, then add the tomatoes and 1/4 teaspoon salt. Simmer until thick, about 6 minutes. Reheat this sauce when ready to serve with the calzones. 4. Meanwhile, divide the pizza dough into 4 balls and roll out each into a 6- or 7-inch circle 1/8 inch thick. 5. On the bottom half of each circle, mound a quarter of the cooled beef mixture, top with 3 tablespoons of the mozzarella. 6. Fold over the top half of the dough to form a semicircle and pinch the edges to seal. Carefully transfer the calzones with a spatula to the prepared baking sheet. Lightly brush with the beaten egg. Cut 2 small slits on top of each to vent steam. 7. Bake the calzones until golden brown, about 20 minutes. Serve with the heated tomato sauce on the side.
We LOVE homemade pizza, it's faster and easier than take out. A few basic tips make this favorite really shine - http://blog.gatheredtable.com/2015/04/13/homemade-pizza-101/