For the filling, stir all ingredients except mozzarella cheese together in a large bowl. Cook pasta according to package directions. Drain, then run cool water over noodles. Pat noodles dry with a paper towel, then fill each with cheese mixture.
For the sauce, place all ingredients in a blender and puree. Store in an air-tight container in the refrigerator until ready to use.
**I recommend preparing the sauce at least 3 hours ahead of time and storing in the refrigerator to allow the flavors to come together, but it will still be yummy if you don't have that extra time.
Pour marinara sauce over the filled manicotti and cover with foil. Bake at 350 degrees Fahrenheit for about 30 minutes. 5-10 minutes before it's done, remove it from the oven, take foil off, and sprinkle mozzarella cheese on top. Return to oven, uncovered, and bake until cheese is bubbly, about 5-10 minutes.