The day before you want to eat the ribs, line a baking sheet with some heavy-duty aluminum foil, and set a cooling rack on the sheet. Wash the rib racks and then thoroughly pat them dry with paper towels and place them on the rack.
To make the dry rub: Set a small skillet (I used a cast iron one) over medium heat. Add the fennel seeds, cumin seeds and chile, if using. Toast the spices, shaking often, until the seeds darken a touch, release their aroma, and smoke ever so slightly. Pour the seeds and the chile into a pestle and mortar or a spice grinder and grind until fine (break the chile up with your hands first if using a spice grinder). Add the brown sugar, paprika and 2 tablespoons salt and stir to combine, smoothing out any lumps in the sugar.
Sprinkle half of the rub over the ribs and massage into the meat evenly. Flip the ribs over and massage the remaining rub into the meat. Cover the ribs tightly with plastic wrap, and refrigerate overnight.
To make the glaze: In a medium saucepan over medium-high heat, warm the peanut oil until shimmering. Add the peppercorns and cook for 30 seconds. Add the shallots, garlic and ginger. Cook until the shallots soften and turn slightly golden, about 5 minutes.
Turn the heat off and add the whiskey. Turn the heat back on, and cook until the whiskey has mostly evaporated. Then add 1/2 cup of water, the tamarind, sweet soy and ketchup. Stir together, and reduce the heat until the mixture is at a simmer. Cook until the mixture has thickened slightly, about 10 minutes. Set aside until you're ready to use it.
When you're ready to cook, preheat the oven to 350 degrees F. Pull the ribs out of the refrigerator and leave on the counter as the oven heats up. Then, remove the plastic wrap from the ribs. Roast the ribs until the meat is tender, about 1 1/2 hours, rotating the pan halfway through to ensure even cooking.
Pull the ribs out of the oven and turn it up to 425 degrees F. Brush the tamarind sauce liberally on both sides of the rib racks, and return the ribs to the oven for about 10 more minutes. Brush with sauce one more time and serve with plenty of napkins!
*Tamarind paste, sweet soy sauce and kecap manis are available in the international aisle of better supermarkets, as well as in specialty Latin and Asian markets