Preheat oven to 400°F; then reduce to 350°F (after zucchini is cooked).
Prepare the sofrito by combining all ingredients (roughly chopped) into a food processor. Pulse until combined. Set aside.
Slice the zucchini lengthwise so that they are 1/2" thick.
Place the sliced zucchini on a lined baking sheet, brush with 1 tbsp of olive oil and season with salt and pepper.
Bake the sliced zucchini in a preheated oven for 20 minutes.
Once the zucchini is done cooking, transfer to a paper towel to remove the excess moisture. Reduce the oven temperature to 350°F.
Meanwhile, prepare the filling.
Heat 2 tbsp of canola oil in a large pan over medium-high heat. Add 2-4 tablespoons of the sofrito (to taste) and cook for 1-2 minutes until fragrant.
Add the ground beef and cook until lightly browned. Add adobo seasoning and continue to cook until fully browned.
Add dissolved bouillon cube to the beef and combine.
Stir in diced tomatoes (or low carb tomato sauce).
Add tomato paste (optional, but recommended if uses fresh diced tomatoes).
Reduce heat to medium and let simmer for approx. 10 minutes, or until most of the liquid is reduced.
Meanwhile, prepare the plantains.
Heat 1/3 cup of canola oil in pan over medium-high heat.
Peel the plantains and slice lengthwise. You should get about 3-4 slices per plantain.
Once the oil is hot, fry the plantains in batches until both sides are golden brown.
Transfer to a paper towel.
Assemble the Pastelón
Layer the cooked zucchini on the bottom of the baking dish.
Top with half of the meat mixture and then half of the whisked egg mixture.
Add half of the grated cheese.
Assemble the fried plantains on top of the mixture.
Finish off the Pastelón with the remaining ground beef mixture and whisked egg (final layer of mozzarella will be added later).
Cover with aluminum foil and bake for 25 minutes.
After 25 minutes, remove the aluminum foil and add the final layer of mozzarella cheese.
Bake uncovered for 10 minutes. Optional, broil at the last few minutes to brown the cheese.
Once the Pastelón is done cooking, remove from oven and let it rest for 15 minutes.
Enjoy!