Preheat the oven to 450°F. Line 2 baking pans with parchment paper. Set aside.
In a large skillet drizzled with olive oil,over medium-high heat, cook sausage for 6-8 minutes until no pink remains. Drain excess fat from pan reserve 2 Tbsp..
To the pan add mushrooms and onions. Cook over medium high for several minutes until the mushrooms are tender and the onions have begun to caramelize.
Season with garlic salt, black pepper and red pepper flakes to taste.
Add spinach and basil and cook just until wilted, about 1 minute. Add cooked turkey sausage back to pan, mix well. Remove from heat and set aside.
To assemble: Flatten dough to about ⅓ of an inch thick and from it roughly into an oval shape about 5 inches wide. Divide filling between calzones, leaving a one inch border on one side.
Spread, each dough piece with ricotta cheese on one half, then top with sausage and vegetable filling. Sprinkle with mozzarella cheese.
Brush the edge with egg wash around the border then gently fold the dough over the filling and crimp edges using a fork or pastry wheel.
Place on baking sheets. Brush with beaten egg wash.
Cut three vents on the top of the calzone with a sharp knife, and sprinkle each lightly with coarse sea salt.
Bake for 18-22 minutes or until golden.
Remove from the oven and let stand for 5 minutes.
Seve with a warm side of marinara sauce for dipping.