After soaking the manicotti, gently pat it dry; this will help the sauce adhere to the pasta.
Preheat oven to 450 degrees. Place tomatoes in small bowl; cover with 1 cup boiling water. Let stand until softened, about 15 minutes. Dry with paper towel, and cut into 1/4-inch dice; transfer to medium bowl.
Fill baking dish with very hot water; place manicotti sheets, one at a time, in water. Let stand 10 minutes until softened.
To tomatoes, add ricotta, 2 tablespoons parsley, basil, egg yolk, nutmeg, salt, and pepper, and mix well to combine. On a clean work surface, place one sheet of manicotti lengthwise. Spoon about 1/3 cup ricotta mixture along front edge; roll to form cylinder. Repeat filling-and-rolling process on all manicotti. Spray 9-by-13-inch baking dish with olive-oil spray; spoon about 1/4 cup tomato sauce on bottom.
Transfer manicotti to the dish in a single layer; cover with remaining 1 1/4 cups tomato sauce, and sprinkle with Parmesan. Cover with foil; bake 10 minutes. Remove foil; bake until top is browned and sauce is bubbling, 12 to 15 minutes. Garnish with remaining teaspoon parsley.