For the tomato sauce: Cook the ground sirloin in a pan over medium heat until it is cooked through, about 10 minutes. Meanwhile, heat the oil in a large pan over medium heat. Add the mushrooms and half the onion and sautee, about 8 minutes. Drain and set aside.
Combine the tomatoes, garlic and remaining onion in a blender and pulse until the mixture is smooth. Transfer to a large stock pot over medium heat. Add the sugar, crushed red pepper, salt, basil, sirloin and mushroom mixture. Bring to a boil and simmer until slightly thickened. Set aside.
For the filling: In a large bowl, combine the ricotta and eggs with a spoon. Add the Parmesan, parsley and pepper, and mix well. Set aside.
For the manicotti crepes: In a large mixing bowl, whisk together the flour and egg. Add the milk and 1/4 cup water and combine.
Spay a nonstick pan with cooking spray and heat over medium heat. Pour or scoop 2 to 4 tablespoons batter into the pan. Tilt the pan in a circular motion so that the batter coats the bottom of the pan evenly. Cook the crepe until the bottom is a light brown, about 2 minutes. Loosen with a rubber spatula, flip over and cook the other side. Repeat this process with the rest of the batter. Set crepes aside.
Preheat the oven to 350 degrees F.
Fill the crepes: Place 2 to 3 tablespoons of the ricotta filling in the middle of each crepe and roll up. Place the crepes, seam-side down, in an 11-by -17-inch baking dish. Cover the crepes with tomato sauce then sprinkle with a thin layer of Parmesan. Bake until bubbly, about 45 minutes. Serve warm.