Roasting the plantains: Bake plantains in a preheated oven at 400ºF [200ºC] for 35 minutes. The plantains will turn a light golden color and will be crispy on the outside, remove from the oven and mash with a pestle.
Cooking garlic: In a pan heat olive oil over very low heat. Stir in garlic and sprinkle with salt. Cover and simmer for 10 minutes, stirring occasionally, and making sure the heat is low enough that the garlic does not burn or change to a dark color. Set aside.
Making plantain balls: Unwrap the plantains. Mash one by one in a mortar and pestle, adding to each plantain ¼ of the oil and garlic. Form each plantain into a ball, or scoop into a bowl and make a hole in the center (see pictures), and serve with the shrimp.