Heat olive oil in a pan over medium heat. Add onion and cook for 2-3 minutes until soft. Add garlic and cook for 30 seconds or until fragrant.
Add ground beef and Italian sausage, breaking it up with a wooden spoon as it cooks. Season with salt and Italian seasoning. Cook for 4-5 minutes until ground beef and sausage are cooked. Remove from burner to cool.
While the meat mixture is cooling, divide the pizza dough into 6 equally sized pieces. Roll each piece into a 1/4" thick circle.
Place 1 heaping tablespoon of ricotta on half of each circle, followed by ¼ cup of the meat mixture and a ¼ cup of shredded mozzarella, making sure to leave a 1-inch border.
Fold half of the dough over, seal and fold edges to create a rope-like border. Transfer to parchment paper-lined baking sheet.
In a small bowl beat egg with 1 tbsp of water to create an egg wash. Brush the egg wash on the top of the calzones, then sprinkle with salt and grated parmesan cheese. Cut three small vents on the top of each calzone.