Remove the skin from the plantains and cut in 1-inch pieces.
Fry plantains in vegetable oil but do not let it burn on the outside. Absorb excess oil with a paper towel.
OR, boil until you can pierce with a fork.
In a food processor combine the cooked plantains, garlic, onion powder, vegetable broth, salt and black pepper and pulse until ingredients are mashed together.
Note: You can also use a large mortar and pestle to mash and mold the mixture using the traditional method.
Remove from food processor, place in a bowl, add butter and mix with a fork. Add more vegetable stock if needed.
Press in small bowls to shape the mofongo like a dome.