Preheat oven to 425ºF.Heat 2 Tbsp. of oil in a large oven-safe skillet (such as cast-iron or stainless steel) over medium heat. Once hot, add panko breadcrumbs; cook for 5 to 7 minutes, tossing often, until golden-brown and crispy. Transfer to a bowl.

Add another 2 Tbsp. oil to the pan. Arrange half of the eggplant slices in the pan, avoiding any overlap. Let cook, undisturbed for 5 minutes. Flip, and cook for another 3 to 4 minutes, until soft and caramelized on both sides. Season eggplant slices with salt and pepper, and transfer to a plate.Add remaining 2 Tbsp. oil to pan, and repeat with second half of eggplant slices. (Note: you may need to do this in 3 batches if you're using a smaller skillet.)While the eggplant is cooking, this is a good time to prep the remaining ingredients. (Grate the Parmesan, finely chop the parsley, and tear/slice the mozzarella.)Once all of the eggplant is sautéed and seasoned, remove pan from heat and let cool for a few minutes.

Pour half of the sauce into the skillet. (Note: if the skillet is still super hot, the sauce may splatter a bit. Proceed with caution.)Next, layer half of the sautéed eggplant slices over the sauce. Top with ¼ cup Parmesan and 3 Tbsp. parsley. Scatter half of the toasted breadcrumbs over the Parmesan and parsley, and finish with half of the torn/sliced mozzarella. Repeat in the same order, starting with remaining jar of sauce and ending with remaining half of mozzarella. If desired, grate extra Parmesan cheese over the mozzarella topping. Drizzle a little extra-virgin olive oil overtop, and carefully transfer pan to the oven. Bake for 20 minutes. Let cool in the pan for 5 minutes.Garnish with remaining fresh chopped parsley (you should have ~2 Tbsp left) before serving.