Don't skip salting the eggplant: it draws out the excess moisture and bitterness, and it's what keeps the slices crisp instead of soggy. For a vegetarian (not vegan) version, use one whole beaten egg instead of the flax egg and grated parmesan instead of the vegan cheese. Leftovers keep in the fridge for up to 3 days; reheat in the oven rather than the microwave to bring the crust back.