1 standing rib roast with 4 - 5 ribs.
6-1/2 tsp dried crushed rosemary
Coarsely ground black pepper
1/2 cup olive oil and then 2 tbsp olive oil
1-1/2 oz dried porcini mushrooms
4 tbsp unsalted butter at room temperature
10 oz sliced white mushrooms
4 medium garlic cloves, minced
2 tbsp flour - gluten free
1-1/2 cups reduced sodium beef broth
3/4 cup dry red wine
2 bunches fresh rosemary for the garnish
Place the roast, fat-side up, in a heavy shallow roasting pan. In a small bowl, mix together 4 tsp of the rosemary, 1 tbsp of the kosher salt, and 2 tsp pepper. Stir in the 1/2 cup of olive oil. Brush the roast on all sides and bottom with this mixture. Make sure roast is at room temperature when you add to the oven.
Put the dried mushrooms in a medium bowl and cover with 2 cups of boiling water and let them steep for 20 min. Strain the mushrooms and like a sponge push out the liquid through a strainer. Collect the juice/liquid in a bowl and save the mushrooms. Then coarsely chop the porcini mushrooms and chop the garlic.
Heat 2 tbsp of butter and the remaining 2 tbsp of olive oil in a large, heavy cast iron pan over medium heat. Add the sliced white mushrooms and cook stirring until browned for 5 to 6 minutes. Add the garlic and chopped porcini mushrooms and cook stirring for another minute or two. Season with 1/2 tsp kosher salt and several grinds of black pepper.
Combine the remaining 2 tbsp butter, remaining 2-1/2 tsp rosemary and flour in a small bowl and mash with a fork to make a paste.
Arrange the rack at lower position and preheat the oven to 350º. Roast until a meat thermometer inserted into the thickest part of the meat registers 125º - 130º F - about 2 hours and 30 minutes.
Transfer the roast to a serving platter and cover loosely with foil. Let rest 35 to 40 minutes while you prepare the sauce. Skim and discard any fat from the pan juices. Set the roasting pan over two burners over medium heat. Add the reserved porcini socking liquid, the north, and the wine. Bring to a boil whisking constantly to scrape up any brown bits on the bottom and sides of the pan into the liquids, for about 2-3 minutes. Add the mushroom mixture and cook for 1 minute more. Whisk in the butter and flour mixture, a tablespoon at a time, and continue to whisk until the sauce thickens, for about 2 minutes. Season with salt and pepper.
To serve, garnish the roast on the platter with several sprigs of fresh rosemary. Slice the roast and pour the mushroom sauce on the meat or serve in a gravy boat.
Enjoy - we will!