On a grill or open flame, scorch eggplant skins until blackened. (Using stem as handle, try to turn eggplants on every side to char as much of the skin as possible.) Place them whole in a heatproof dish and cover with a tight-fitting lid or plastic wrap. Let eggplants steam in the residual heat until they turn limp. Once they have had a chance to cool, gently peel away skins and discard. Set peeled eggplants aside.
In large pan, heat about 1 tablespoon oil till hot. Add onion & garlic and saute until light brown. Mix in ground pork and saute until cooked. Add diced tomato and cook until softened. Add fish sauce and cook over medium heat 5 minutes or until moisture has evaporated. Remove mixture from heat and set aside to cool.
In flat baking dish or pie pan, whisk eggs until frothy. Add both eggplants, laying them side by side with stem ends sticking up and out of the bowl together. Using a fork, gently mash eggplant meat until flattened. Add pork mixture and make sure it and eggplant are well-coated with beaten eggs. Season with salt and pepper and set aside.
In large nonstick skillet on medium high, heat 1 tablespoon oil. Carefully slide eggplant and egg mixture into pan, with stem ends sticking up together. Lower flame to medium heat. Once egg mixture looks opaque around edges, cover pan with a large plate (should be at least 1 inch bigger than pan circumference) and quickly turn pan upside down so the eggplant mixture lands on the plate (the cooked side should be on top). Return pan to stove, add a little bit more oil on medium heat. Carefully slide the eggplants uncooked side down, into the pan. Lower heat to medium and cook until eggs are cooked through.