Preheat oven to 300°F (150°C). Pat ribs dry with paper towels. Turn ribs bone-side up and use a paring knife to loosen the silver skin (membrane) at one end, then grab with a paper towel and pull it off to expose bones — this helps flavors penetrate and yields more tender ribs.

Season

Combine kosher salt, black pepper, garlic powder, smoked paprika, and ground cumin in a small bowl. Rub olive oil over both sides of the ribs, then massage the dry spice mix evenly all over the ribs on both sides.

Prepare for baking

Place each rack of ribs on a large sheet of heavy-duty aluminum foil, meaty side up. Add 1/2 cup water to the bottom of each foil packet (or a single cup split between two racks) to create steam during cooking. Seal packets tightly so steam stays inside.

Slow cook

Place foil-wrapped ribs on a baking sheet and bake in the preheated oven for 2 to 2.5 hours (for 2 lbs racks; adjust to 2.5–3 hours for larger racks) until meat is very tender and pulls back from the bone about 1/4–1/2 inch. Check at 2 hours for tenderness.

Make Hot Chilli Glaze

While ribs cook, combine tomato ketchup, brown sugar, Sriracha, chili flakes, soy sauce, honey, and lime juice in a small saucepan. Warm over medium-low heat and stir until sugar dissolves and glaze thickens slightly, 5–7 minutes. Taste and adjust heat by adding more Sriracha or a pinch more chili flakes if you want a hotter kick. Keep warm on lowest heat, stirring occasionally.

Finish Ribs & Glaze

Unwrap and baste

Carefully open the foil packets (watch for hot steam). Transfer ribs to a rimmed baking sheet or grill. Increase oven temperature to 425°F (220°C) or preheat a grill to medium-high for finishing.

Brush a generous layer of the hot chilli glaze over the meaty side of the ribs. Place ribs in the oven or on the grill and cook, uncovered, for 8–12 minutes until glaze is bubbly and tacky. For extra char, move briefly under a broiler (2–3 minutes) or over direct grill heat, watching closely so glaze doesn't burn.

Turn ribs over, brush the bone side lightly with glaze, and return to heat for 3–5 minutes more. Remove when glaze is sticky and caramelized to your liking.

Garnish & Serve

Transfer ribs to a cutting board and let rest 5 minutes. Slice between the bones into individual portions.

Sprinkle chopped cilantro, chopped mint (if using), sliced green onions, and toasted sesame seeds evenly over the sliced ribs. Serve with lime wedges for squeezing over the ribs at the table.

Optional: Serve with extra warmed glaze on the side for dunking or drizzling.