The Best Pork Loin Roast

Heat the oven to 350°F. Pluck the fresh rosemary needles off of the stems until you have 2 or 3 tablespoons of the needles. Peel the garlic and finely chop it together with the rosemary. Set the mixture aside in a tiny bowl.

When your oven is ready, place the butter in a 9x13 pan or roaster (see notes) and set the pan on the center oven rack for about 4 minutes, to allow the butter to melt.

While the butter is melting, place the roast horizontally in front of you, with the fat on top. Use a sharp, serrated knife to cut vertical slits in the pork. Make the slits about four inches long, two inches deep and space them at least an inch apart. (See the video and photo in the post.)

Stuff the rosemary-garlic mixture into the slits you made in the roast. Wash your hands well.

When the butter is melted, take the pan out of the oven. Still wearing gloves or mitts, tilt the pan back and forth a bit so the melted butter coats the whole bottom.

Set the pork on top of the melted butter in the pan. Season the roast with the salt and pepper. Pour the olive oil over the top.

Bake the pork initially for 30 minutes, uncovered. During that time, chop up half an onion. After the pork has cooked for 30 minutes, remove the pan from the oven. Add the chopped onion to the bottom of the pan, around the pork.

Make sure to wear gloves/mitts again as you put the pork back in the oven to roast for another 25-30 minutes, or until the internal temperature reaches 150 degrees F (or 145 F if you want it medium-rare). Note that a metal pan will cook the pork faster than a glass pan.

Let the pork rest for 3 minutes before slicing it. (Or rest it for 10 minutes to let the internal temperature rise to 160 degrees F for a medium-cooked roast.) Use a large knife with a smooth blade to slice the meat. To serve, spoon the juices and onions on top of the sliced pork.

Store leftover pork covered in the refrigerator for up to four days. You should be able to freeze the sliced pork for up to three months.