Pork Tenderloin with Fennel

Preheat oven to 425 degrees F.

Mash garlic, fennel seeds and salt together on a cutting board with the flat side of a large knife. Place in a small bowl; stir in pepper and 1 1/2 teaspoons oil. Rub the fennel-seed mixture evenly over pork, pressing it into the crevices. Fold the thin tails underneath and secure with butcher's string or a toothpick.

Heat a large ovenproof skillet over medium-high heat. Add the pork and cook until lightly browned on one side, about 1 1/2 minutes. Turn the tenderloins over, transfer the skillet to the oven and roast until the internal temperature registers 145 degrees F, 15 to 17 minutes.

Meanwhile, heat the remaining 1 1/2 teaspoons oil in a heavy saucepan over medium-low heat. Add fennel and onion and cook, stirring often, until softened, 3 to 5 minutes. Add broth and bring to a simmer. Cover and cook over low heat until the vegetables are tender, 10 to 15 minutes. Transfer to a blender or food processor and puree. Return to the saucepan and keep warm.

When the pork is done, transfer it to a carving board, cover loosely and keep warm. Place the pan (be careful, the handle will be hot) over medium-high heat. Add wine and bring to a boil, stirring. Boil until reduced by half, about 2 minutes. Add to the fennel sauce, along with sour cream (if using). Taste and adjust seasonings. Remove the string or toothpick from the pork and carve into 1/2-inch-thick slices. Spoon the sauce onto plates and fan pork slices over top. Garnish with a few fennel fronds.