Heat a Dutch oven over medium-high heat and add the onion, garlic and bacon. Cook until the bacon is crisp, about 12 to 15 minutes. Stir in the stock and 1 cup of the heavy cream. Reduce the heat to medium-low and add the plantains. Simmer the mixture until the plantains are tender, about 5 to 8 minutes. Add the remaining 1/4 cup of heavy cream and the salt and pepper. Mash together until well combined. Transfer to a serving bowl and serve.
*Cook's Note: Add a little more stock if the mash is too dry.