Butter a square baking dish with the butter.
In a large bowl, combine the beef, onion, pepper, garlic, cilantro, adobo, oregano, vinegar and sazón, mix until well blended.
Heat 2 tbs oil in a large frying pan and add the meat mixture, cook stirring constantly until the meat is browned all sides.
Add the bay leaves, olives, tomato sauce and raisins, mix and let it simmer for around 10 minutes, set aside.
Heat oil (we used deep fryer) enough for frying the plantains.
Fry the plantains for around 2 - 3 minutes each side or until golden and crispy.Drain them on a dish with kitchen paper, set aside.
Take the previously prepared dish and start with a layer of plantains, then beef, then the cheese.
Repeat the process finishing with plantains and cheese.
In a bowl whisk the eggs with the milk, pour this mixture over the Pastelón.Let sit for a minute for allowing the egg to soak in.
Top with a little more of cheese and bake on a previously pre-heated oven at 180°C for 20 minutes or until golden brown and set.