Preheat oven to 425 degrees F.
Prepare the chicken by removing the insides, washing it well, and placing it in a large baking pan or on a rotisserie. Lightly oil the chicken and roast until the juices run clear.
To prepare the mojo: peel and segment the grapefruit and place in a bowl. Add the red onion, cilantro, lime juice, and tequila, and let the mixture marinate for 2 hours in the refrigerator.
Peel and dice the potatoes, and cook in salted boiling water until tender. Drain the potatoes, add the heavy cream, minced garlic, salt, and pepper, and mash until smooth.
To make the tostones, peel and slice each plantain approximately 2-inches thick. In a deep skillet, heat the oil to 375 degrees F. Place the plantains in the oil and cook until both sides are slightly brown. Remove from the oil and drain on a paper towel. Once they have cooled, using a rolling pin, mash them until they are 1/4-inch thick. Return them to the hot oil and cook until golden brown. Season with salt while still hot.
To serve, place the mashed potatoes in the center of the plate, add the chicken on top, a spoonful of the grapefruit mojo, and decorate with a few tostones chips.
Recipe courtesy of James Porter, Biltmore Hotel, Coral Gables, FL