Trim both ends of each green plantain. Make a lengthwise shallow slit through the thick peel and pry the skin away from the flesh with your fingers or a small knife. Cut each peeled plantain into 1- to 1.5-inch thick rounds (or diagonally into 1 to 1.5-inch pieces) so they cook evenly.

Cook

Place the plantain pieces in a medium saucepan and add about 6 cups of water (enough to cover by 1 inch) and 1 teaspoon salt. Bring to a boil over high heat, then reduce to a medium simmer. Cook until a fork pierces plantain easily and the pieces are very soft, 15–20 minutes depending on size. Drain well in a colander, reserving a few tablespoons of cooking liquid.

Flavor base

While the plantains cook, heat 1 tablespoon olive oil and 2 tablespoons unsalted butter in a small skillet over medium heat until butter melts. Add the finely chopped onion and sauté 3–4 minutes until translucent. Add the minced garlic and cook 30–45 seconds until fragrant but not browned. Remove from heat.

Mash & finish

Return the drained plantain pieces to the warm saucepan or a large mixing bowl. Use a potato masher or sturdy fork to begin mashing while the plantains are hot. Add the sautéed onion and garlic with any pan juices, 2 tablespoons butter, 1 tablespoon lime or lemon juice, 1/2 teaspoon freshly ground black pepper, and 2 tablespoons chopped cilantro or parsley.

If the mash is very stiff, add 1–2 tablespoons of the reserved cooking liquid at a time until you reach the desired creamy consistency. Taste and adjust salt (add up to another 1/2 teaspoon if needed) and acidity.

Stir in optional add-ins if using: 2 tablespoons scallions, 2 tablespoons crumbled queso fresco or grated Parmesan, and/or 1/4 teaspoon red pepper flakes for heat. Mix thoroughly but avoid overworking the plantains — you want a slightly rustic texture rather than completely puree-smooth.

Serve warm, garnished with a little extra chopped cilantro or parsley and a drizzle of olive oil or a small pat of butter.