Tangy, Spicy Grilled Ribs

Preheat oven to 325°. Combine crushed red pepper flakes, kosher salt, light brown sugar, paprika, and black pepper in a small bowl.

Cut each rack of ribs in half for easier maneuvering on the grill. Place ribs on a large rimmed sheet pan and season on both sides with the spice rub. Wrap each rack of ribs in aluminum foil and put back on the sheet pan.

Roast ribs in the oven until tender, nearly falling off the bone, about 2–2.5 hours for St. Louis and 2.5–3 hours for baby back. Let cool a bit before unwrapping, keeping all the juices. Pour juices into a measuring cup or medium bowl.

For the sauce, add mustard, vinegar, and light brown sugar to the bowl with juices. Adjust with more vinegar or sugar to your liking.

Assuming you’re grilling, heat grill to medium high. Baste ribs on one side with sauce and place basted-side down on grill. Close the grill and cook until charred, about 5-10 minutes. Flip and baste again until charred to liking.

If not grilling, baste ribs and broil until lightly charred.