How to Make It
Preheat the oven to 400°. Bring a large pot of water to a boil. Add the ribs, cover and simmer over low heat for 10 minutes. Using tongs, transfer the racks to 2 rimmed baking sheets, meaty side up. Rub with the oil and garlic and season with cayenne, salt and black pepper. Bake the ribs for 30 minutes.
Meanwhile, in a small saucepan, cook the guava paste and water over low heat, mashing with a fork, until melted and smooth, about 5 minutes. Add the soy sauce and simmer for 2 minutes, stirring. Remove from the heat, stir in the lime juice and season with salt and pepper.
Raise the oven temperature to 500°. Brush the ribs with the guava glaze, spreading it all over the top. Bake 2 racks at a time on the top shelf of the oven for about 10 minutes, or until the ribs are browned and cooked through. Cut in between the ribs and arrange them on a platter or on plates. Serve hot.