Ingredients

• 1 1/2 lb firm-ripe peaches
• 1/2 lb tomatoes
• 1/2 cup chopped red onion (1 medium)
• 1 tablespoon minced peeled fresh ginger
• 1 teaspoon kosher salt
• 1 tablespoon vegetable oil
• 1 1/2 teaspoons curry powder
• 2 tablespoons sugar
• 1 tablespoon fresh lime juice
• 3 scallions (white and pale green parts only), trimmed
• 1 tablespoon chopped fresh thyme
• 2 teaspoons kosher salt
• 1/2 teaspoon ground allspice
• 1/4 teaspoon black pepper
• 2 tablespoons fresh lime juice
• 1 tablespoon molasses (not robust or blackstrap)
• 1 teaspoon Scotch bonnet or habanero hot sauce*, or to taste
• 2 pork tenderloins (1 3/4 to 2 lb total)
• 2 tablespoons vegetable oil for basting
• Special equipment: an instant-read thermometer

Instructions

1. Cut a shallow X in bottom of each peach and tomato with a sharp paring knife and blanch in 2 batches in a 4-quart saucepan of boiling water 10 seconds. Transfer peaches and tomatoes with a slotted spoon to a bowl of ice and cold water and let stand until cool enough to handle. Peel peaches and tomatoes, then halve peaches lengthwise and pit. Cut peaches into 1-inch pieces. Coarsely chop tomatoes.
2. Cook onion, ginger, and salt in oil in a 3-quart heavy saucepan over moderate heat, stirring occasionally, until softened, 3 to 4 minutes. Add curry powder and cook, stirring constantly, 1 minute. Add peaches and tomatoes with any juices, sugar, and lime juice and simmer, uncovered, stirring occasionally, until mixture is thick and peaches are tender but still hold their shape, about 8 minutes. Transfer to a bowl and cool, uncovered, then chill, covered, at least 8 hours.
3. Marinate pork: Combine scallions, thyme, salt, allspice, pepper, lime juice, molasses, and hot sauce in a blender and blend until smooth. Put pork in a nonreactive dish and rub all over with marinade. Marinate, covered and chilled, turning occasionally, 8 hours. Bring to room temperature before grilling.
4. Combine scallions, thyme, salt, allspice, pepper, lime juice, molasses, and hot sauce in a blender and blend until smooth. Put pork in a nonreactive dish and rub all over with marinade. Marinate, covered and chilled, turning occasionally, 8 hours. Bring to room temperature before grilling.
5. Grill pork: Prepare grill for cooking over medium-hot charcoal (moderate heat for gas); see "Grilling Procedure," below. Discard any marinade remaining in dish, then brush pork lightly with oil and grill on a lightly oiled grill rack, turning occasionally and basting frequently with oil, until thermometer inserted diagonally into center of meat registers 145°F, 15 to 25 minutes. Transfer pork to a cutting board and let stand 15 minutes. (Internal temperature will rise to about 155°F.) Serve pork with relish.
6. Prepare grill for cooking over medium-hot charcoal (moderate heat for gas); see "Grilling Procedure," below.
7. Discard any marinade remaining in dish, then brush pork lightly with oil and grill on a lightly oiled grill rack, turning occasionally and basting frequently with oil, until thermometer inserted diagonally into center of meat registers 145°F, 15 to 25 minutes.
8. Transfer pork to a cutting board and let stand 15 minutes. (Internal temperature will rise to about 155°F.) Serve pork with relish.
9. Grilling Procedure If using a charcoal grill, open vents on bottom of grill, then light charcoal. When charcoal turns grayish white (about 15 minutes from lighting), hold your hand 5 inches above grill rack to determine heat for charcoal as follows: Hot: When you can hold your hand there for 1 to 2 seconds Medium-hot: 3 to 4 seconds Low: 5 to 6 seconds If using a gas grill, preheat burners on high, covered, 10 minutes, then, if necessary, reduce to heat specified in recipe.
10. If using a charcoal grill, open vents on bottom of grill, then light charcoal. When charcoal turns grayish white (about 15 minutes from lighting), hold your hand 5 inches above grill rack to determine heat for charcoal as follows:
11. Hot: When you can hold your hand there for 1 to 2 seconds
12. Medium-hot: 3 to 4 seconds
13. Low: 5 to 6 seconds
14. If using a gas grill, preheat burners on high, covered, 10 minutes, then, if necessary, reduce to heat specified in recipe.
15. *Available at most supermarkets and kitchenmarket.com.