Pork Tenderloin with Blackberry Barbecue Sauce

For sauce: In a medium saucepan, bring blackberries and 2 tablespoons brown sugar to a boil over medium-high heat. Reduce heat, and simmer for 10 minutes, mashing berries occasionally with a fork. Place a fine-mesh sieve over a bowl. Press blackberry mixture with a spatula or a whisk through sieve. (There should be about 1¼ cups juice.) Discard seeds.

Return blackberry juice to saucepan. Whisk in ketchup, chile pepper, vinegar, paprika, garlic powder, salt, pepper, and remaining 1 tablespoon brown sugar; bring to a simmer over medium heat. Reduce heat to medium-low; cook for 10 minutes, whisking occasionally. Remove from heat. Reserve ⅔ cup sauce for serving.

Preheat oven to 375°. Line a large rimmed baking sheet with parchment paper.

For pork: Sprinkle pork with salt and pepper. In a large skillet, heat oil over medium-high heat. Add pork; cook, turning occasionally, until browned, about 6 minutes. Place pork on prepared pan. Brush with sauce.

Bake until a food thermometer inserted in thickest portion registers 145°, about 25 minutes, basting occasionally with sauce. Let stand for 10 minutes. Serve with reserved ⅔ cup sauce. Garnish with blackberries and chile pepper, if desired.