Peel the plantains and cut them into 1-inch pieces.
In a large skillet, heat oil over medium heat. Fry the plantain pieces in batches until golden brown, about 3-4 minutes per side.
Remove the plantains from the oil and drain them on paper towels. Season with salt while hot.
In the same skillet, add olive oil and garlic; sauté until fragrant, about 1 minute. Add the shrimp, salt, and pepper; cook until shrimp are pink, about 3-4 minutes.
Pour in the chicken or vegetable broth and let simmer for 2-3 minutes until slightly thickened.
In a large bowl, mash the fried plantains with a fork or a mortar and pestle until smooth but still somewhat chunky.
Incorporate the sautéed shrimp mixture into the mashed plantains, mixing well to combine.
Serve the mofongo hot, garnishing with fresh cilantro.