Authentic Beef Stroganoff | The Cook's Cook

Ingredients

• 907 grams (2 pounds) beef tenderloin*, thinly sliced into bite-size pieces
• 454 grams (1 pound) fresh mushrooms (such as a mix of baby bella/cremini and shiitake mushrooms), cleaned and thinly sliced**
• 15 grams (1 tablespoon) dried porcini powder (optional)
• 1 medium yellow or white onion, diced
• 3 cloves garlic, minced
• 60 grams (4 tablespoons) butter, or as needed
• Vegetable oil, if needed
• 709 ml (3 cups) home made or unsalted canned beef stock, plus additional as needed
• 60 grams (1/4 cup) ketchup or tomato paste***
• 120 grams (1/2 cup) quick-dissolving flour or all-purpose flour
• 237 ml (1 cup) sour cream
• Kosher salt
• Fresh ground black pepper
• 30 ml (2 tablespoons) fresh thyme leaves, plus additional for garnish
• Cooked buttered egg noodles or basmati rice, for serving