Preheat an oven to 450°F. Evenly space out 2 oven racks.
Lay the eggplant in an even layer on two parchment-lined rimmed baking sheets. Brush both sides of the eggplant slices with oil, then season each side with oregano, salt and pepper. Bake for 15 minutes, then flip and bake until other sides are lightly browned (about 10 minutes more). Set aside. Reduce oven temperature to 400°F.
Add both mozzarella cheeses, Parmesan cheese and chopped herbs to a medium bowl, tossing to combine.
Spread 1 cup of tomato sauce in an even layer in the bottom of a 9 x 13 baking dish. Top with 1/3 of the eggplant, arranged in an even layer. Top the eggplant with 1/3 of the cheese mixture. Repeat even layers two more times with remaining ingredients (so you’ll finish with a layer of cheese on top).
To make the topping, place bread crumbs, garlic, olive oil, herbs, salt and pepper in a medium bowl, tossing to combine. Spread bread crumbs out evenly over the baking dish.
Bake until the top is golden brown and the sides are bubbling (45 to 50 minutes). Let cool for 10 minutes before serving.