1. Heat oven to 375 degrees . Place sliced tomatoes in a single layer on paper towels. Sprinkle one side of tomatoes with 1/4 tsp of the salt; let stand for 10 minutes. Gently pat salted side of tomatoes with paper towels to absorb some of the moisture. Flip tomatoes and sprinkle with remaining 1/4 tsp of the salt.
2. Meanwhile, fit piecrust into a 9-inch pie plate. Sprinkle bread crumbs evenly on the bottom. Place half the mozzarella over the bread crumbs, along with a third of the tomatoes and a third of the basil. Sprinkle with 2 tbsp of the Parmesan. Layer with a third of the tomatoes, a third of the basil and remaining mozzarella. Layer with remaining tomatoes, basil and Parmesan. Season with pepper and, if desired, brush edges of crust with beaten egg.
3. Bake at 375 degrees for 40 to 45 minutes, until crust is browned. Cool 10 to 15 minutes before slicing.