Peel the plantains and cut them into thin strips about ¼” in thickness. Preheat the oven to 350° f.
In a deep skillet, add vegetable oil. Heat oil over medium-high heat. Add the plantain slices and fry for approximately 2 minutes, stirring and turning occasionally.
Remove the plantains using a slotted spoon and transfer them to a plate lined with paper towels to absorb excess oil and set aside.
In a medium bowl, combine milk, beaten eggs, sugar, cinnamon, guava paste, cheese cubes and fried plantain. Mix well.
Pour mixture into a greased baking pan, sprinkle grated cheese on top and bake for 30 minutes.