Heat 1/4 cup of extra virgin olive oil in a large covered skillet over medium-high heat.
Cook the cut chicken in the oil until browned on all sides, then remove it from the skillet.
Arrange 450 grams of peeled and cut potatoes in the skillet to cover the bottom.
Scatter 18 peeled garlic cloves over the potatoes.
Place the browned chicken on top of the garlic and potatoes.
Sprinkle 1 teaspoon of ground black pepper, 3/4 teaspoon of salt, and 2 tablespoons of chopped parsley over the chicken.
Pour 1 1/2 cups of sherry and 1/2 cup of port wine over everything.
Cover the skillet and simmer over low heat for approximately 45 minutes, or until the potatoes and chicken are cooked through.