Preparation Preheat oven to 350°F. Puree 1/2 cup chopped onion, 2 tablespoons oil, 2 teaspoons cardamom, and garlic in processor. Spread 1/2 cup chopped onion in center of large roasting pan; top with pork. Sprinkle pork generously with salt and pepper; coat with onion puree. Toss mushrooms, remaining 1/2 cup onion, and 3 tablespoons oil in bowl; sprinkle with salt and pepper; arrange around pork. Roast pork 1 hour. Spoon mushrooms into large saucepan. Add 1 1/2 cups broth to roasting pan. Roast pork until thermometer inserted into thickest part registers 145°F, about 20 minutes longer. Transfer pork to platter; tent loosely with foil (temperature will rise 5 to 10 degrees as roast stands). Scrape juices from roasting pan into saucepan with mushrooms. Add cream, remaining 1/2 cup broth, and 1/4 teaspoon cardamom to pan; bring to boil. Blend flour and butter in small cup; mix into mushroom sauce. Cook sauce, stirring often, until reduced enough to coat spoon, about 5 minutes. Season sauce with salt and pepper; serve with pork.
Preparation Preheat oven to 350°F. Puree 1/2 cup chopped onion, 2 tablespoons oil, 2 teaspoons cardamom, and garlic in processor. Spread 1/2 cup chopped onion in center of large roasting pan; top with pork. Sprinkle pork generously with salt and pepper; coat with onion puree. Toss mushrooms, remaining 1/2 cup onion, and 3 tablespoons oil in bowl; sprinkle with salt and pepper; arrange around pork. Roast pork 1 hour. Spoon mushrooms into large saucepan. Add 1 1/2 cups broth to roasting pan. Roast pork until thermometer inserted into thickest part registers 145°F, about 20 minutes longer. Transfer pork to platter; tent loosely with foil (temperature will rise 5 to 10 degrees as roast stands). Scrape juices from roasting pan into saucepan with mushrooms. Add cream, remaining 1/2 cup broth, and 1/4 teaspoon cardamom to pan; bring to boil. Blend flour and butter in small cup; mix into mushroom sauce. Cook sauce, stirring often, until reduced enough to coat spoon, about 5 minutes. Season sauce with salt and pepper; serve with pork.