4-rib standing rib roast, about 8 oounds (4 kg), tied
2 tablespoons unsalted butter, at room temperature
3 tablespoons chopped fresh rosemary
salt and freshly ground pepper

Yorkshire Pudding:
3 extra-large eggs
1 1/2 cups (12 fl oz/375 ml) whole milk
1 1/2 cups (7 1/2 oz/235 g) all-purpose (plain) flour
1 1/4 teaspoons kosher salt
canola oil, if needed
2 cups (16 fl oz/500 ml) beef or chicken stock

Remove the roast from the refrigerator about 1 hour before roasting. Position a rack in the lower third of the oven and preheat to 450°F (230°C). Rub the roast on all sides with the butter and rosemary. Season with salt and pepper.

To make the Yorkshire pudding batter, combine the eggs and milk in a blender and process just to combine. Add the flour and salt and process until smooth, about 30 seconds. Cover and refrigerate until needed.

Place the roast, rib bones down, in a roasting pan. Roast for 20 minutes. Reduce the heat to 350°F (180°C). Continue to roast until an instant-read thermometer inserted into the thickest part away from the bone registers 120°-130°F (52°-54°C) for rare to medium-rare, about 1 1/4 – 1 3/4 hours longer. Transfer to a carving board and loosely tent with aluminum foil. Let rest for 30 minutes. Position a rack in the upper third of the oven and raise the heat to 450°F (230°C).

Spoon the fat from the roasting pan into a small bowl. Add canola oil if needed to total 1/4 cup (2 fl oz/60 mil) and reserve. Pour the stock into the roasting pan, place the pan on the stove top over low heat, and scrape the pan bottom to loosen browned bits, stirring until dissolved. Pour the contents of the pan through a medium-mesh sieve into a measuring pitcher and reserve.

Put 1 teaspoon of the reserved fat in each of 12 nonstick standard muffin cups. Place in the oven to heat for 5 minutes. Pour 3-4 tablespoons of the batter into each hot muffin cup, filling them about two-thirds full. Return the pan to the oven and Reduce the heat to 425°F (220°C). Bake until puffed and golden and a knife inserted into the center of 1 pudding comes out clean, about 30 minutes

While the puddings are baking, prepare the jus:
Pour the pan juices mixture into a saucepan, bring to a boil over high heat, and cook until Reduced by one-third, about 5 minutes. Season with salt and pepper. Set aside and keep warm.

Remove the strings and cut along the rib bones to hrefease the meat in a single large piece. Cut across the grain into thick slices. Serve with a little jus spooned over each slice. With the tip of the knife, lift each pudding from the muffin pan and serve with the roast.