1. Preheat oven to 450 degrees. Lightly oil a heavy-bottomed metal roasting pan. In a food processor, combine oil, garlic, rosemary, fennel seed, 2 teaspoons salt, and 1 teaspoon pepper. Pulse until a paste forms.

2. With a paring knife, gently score the pork's fat layer, making 10 to 15 small 1/2-inch-deep cuts all over. Rub pork with garlic paste, pushing it into cuts. With kitchen twine, tie pork in 1-inch increments and transfer to pan.

3. Roast until golden brown, 30 minutes. Reduce heat to 300 degrees and roast until an instant-read thermometer inserted into center reads 170 degrees, about 2 1/2 hours. Transfer pork to a cutting board, cover with foil, and let rest 15 minutes before slicing.

4. Meanwhile, pour pan drippings into a small bowl and skim fat. Set pan over medium, add wine, and cook, stirring and scraping up browned bits, until wine is reduced by half, 4 minutes. Add flour and whisk to combine. Cook 1 minute. Slowly whisk in drippings and broth. Cook, whisking, until sauce thickens slightly, 3 minutes. Serve with pork.