Immerse the untreated cedar plank in water, place a weight on it to keep it submerged. Soak for 4 to 24 hours.
To make the salsa: In a large saut° pan combine the pineapple, sugar, vinegar, lime juice, jalapeño, cumin, salt, and pepper. Bring to a boil and cook over medium-high heat until thickened, 7 to 10 minutes. (If there is still a lot of liquid left, use a slotted spoon to transfer the pineapple to a bowl and continue to cook the liquid over high heat for 5 minutes more, then pour the liquid over the pineapple.) Mix in the onions and basil. Season with salt, if desired.
To make the rub: In a small bowl combine the rub ingredients. Trim any excess fat from the pork loin. Spread the rub over the roast and place on the cedar plank. Allow to stand at room temperature for 20 to 30 minutes before grilling.
Grill over direct medium heat until the internal temperature reaches 155° F, about 1 hour. Carefully remove the roast and plank from the grill and loosely cover the roast with foil. Allow to rest for 3 to 5 minutes before carving. Serve warm with the pineapple salsa.
Servings: 6