Step 1

Preparation Preheat oven to 350°F with rack in middle.

Step 2

Crush fennel seeds with a mortar and pestle or wrap in a kitchen towel and crush with bottom of a heavy skillet.

Step 3

Pat pork dry, then sprinkle with crushed fennel seeds and 1/2 teaspoon each of salt and pepper. Cut fennel bulbs lengthwise into 1/2-inch wedges.

Step 4

Heat oil in a 12-inch oven-proof heavy skillet over medium-high heat until it shimmers. Brown pork on all sides, about 6 minutes total, then transfer to a plate. Sauté garlic and fennel wedges in skillet until fennel is golden brown, about 6 minutes. Add wine, stirring and scraping up brown bits, then stir in broth and butter. Put pork on top of fennel and transfer skillet to oven. Roast until an instant-read thermometer inserted into center of pork registers 145 to 150°F, about 15 minutes. Transfer pork to a cutting board and let rest 10 minutes.

Step 5

Meanwhile, transfer skillet to stovetop (handle will be hot) and boil, stirring occasionally, until most of liquid has evaporated. Stir in lemon juice and 1/4 cup chopped fennel fronds. Thinly slice pork and serve over fennel with sauce.