Steamed white rice is a common accompaniment for this classic Filipino dish.
Place tamarind pulp in a bowl, and add boiling water. Let soak for 15 minutes. Pour through a fine sieve; discard solids. You should have 2 cups liquid.
Stir together tamarind liquid, garlic, ginger, soy sauce, and brown sugar until sugar has dissolved.
Place ribs on a roasting pan or a rimmed baking sheet. Pour marinade over ribs, and cover pan with plastic wrap. Marinate in refrigerator overnight, flipping ribs once while marinating.
Preheat oven to 300 degrees. Let ribs stand at room temperature for 20 minutes. Cover pan tightly with parchment and then foil, and cook until meat pulls away easily from bones, 1 1/2 to 1 3/4 hours. Transfer ribs to a rimmed baking sheet; tent with parchment and then foil.
Pour pan juices into a saucepan, and skim off excess fat (you should have about 3 cups juices). Boil the juices over medium-high heat until reduced to about 1 cup, about 20 minutes. Pour 1/2 cup sauce into a small bowl.
Preheat the broiler. Brush both sides of ribs with sauce in bowl. Broil ribs until sauce is bubbling and blackened in places, about 2 minutes. Brush broiled ribs with remaining sauce in pan. Let stand 5 minutes. Cut into 1-rib servings, and arrange on a platter.