Serve this flavorful pork tenderloin from food writer J.M. Hirsch's "High Flavor, Low Labor," then use the leftovers to make his Pulled-Pork Sandwich recipe.
Make the seasoning blend: In a small bowl, mix together all ingredients. Transfer half of blend to a large saucepan; set remaining seasoning blend aside.
Make the brine: Add 3 cups water, brown sugar, and salt to saucepan with seasoning blend. Set pan over high heat and bring to a boil; cook until sugar and salt have dissolved. Remove from heat; add ice and stir until cooled.
Make the pork loin: Place pork in a large resealable plastic bag. Add brine to bag; seal and refrigerate for 3 to 6 hours.
Preheat oven to 375 degrees.
Scatter onions over bottom of a roasting pan. Remove pork from brine; pat dry with paper towels. Rub reserved seasoning blend over tenderloins and place pork on top of onions. Transfer to oven and roast until pork reaches 145 degrees on an instant-read thermometer, about 30 minutes.
Let pork stand in roasting pan 15 minutes before slicing and serving.