There are few things which please dinner guests more than seeing a beautifully cooked roast emerge from the kitchen, and Mario Batali’s Tuscan-style pork roast will not disappoint. A quick and easy pan sauce made from the roasting liquid makes for a flavorful and delicious accompaniment.
Preheat the oven to 400 degrees.
Smash 12 garlic cloves into a paste and place in a roasting pan large enough to hold the pork loin. Line the onions on the bottom of the pan over the garlic. Remove the green frilly tops of the fennel, chop, and set aside. Remove the fibrous ribs above the actual bulb and slice the fennel bulbs into ¼-inch-thick slices and place into the roasting pan with the onions and garlic.
Season the pork aggressively all over with the salt, pepper, and fennel pollen and make 6 incisions along the bones 3 inches deep. Stuff 2 cloves of garlic into each incision and place the pork roast into the roasting pan on top of the onions and garlic. Pour the milk over the roast and place in the oven for 65-75 minutes, or until a meat thermometer inserted into the roast at the thickest part (without allowing it to touch the bone) reads 145 degrees.
Remove the pan from the oven and place the roast on a warm platter. Place half of the cooked onions and all of the drippings and liquid into a blender and blend for about 30 seconds. (Start at a low setting and gradually increase the speed since hot liquids expand when blended.) While the motor is running, drizzle in the olive oil until the mixture is smooth and thick. Season the sauce with salt and pepper, to taste.
Arrange the remaining onions in a pile on the serving platter and carve the pork off the bone. Slice the meat into ½-inch-thick slices and arrange over the onions. Pour a few tablespoons of the sauce from the blender over the meat and serve immediately with the rest of the sauce on the side.