Slow Cooker Beef, Carrot & Mushroom Stew

• In a medium microwave-safe bowl (large bowl for 8 servings), whisk together vinegar, Worcestershire, soy sauce, stock concentrates, tomato paste, garlic powder, thyme, paprika, half the flour, and 11⁄4 cups water (all the flour and 21⁄2 cups water for 8) until everything is incorporated and mixture is mostly smooth (it’s OK if some lumps remain!). • Add 3 TBSP butter (6 TBSP for 8) to bowl. • Microwave for 90 seconds, then whisk for 10 seconds. Repeat microwaving and whisking twice, until butter has melted and gravy is thick enough to coat the back of a spoon. Whisk until mostly smooth, 30 seconds more.

• Place beef*, carrots, onions, and mushrooms in a 5- to 6-quart slow cooker; season generously with salt and pepper. Add gravy and stir until everything is evenly coated. • Cover and cook on high until beef is tender, 31⁄2 hours (4 hours for 8 servings).

• When stew has 20 minutes left, place potatoes in a large pot with enough salted water to cover by 2 inches. Bring to a boil and cook until tender, 15-20 minutes. • Reserve 3⁄4 cup potato cooking liquid (1 1⁄2 cups for 8 servings), then drain.

• Return potatoes to pot along with 3 TBSP butter (6 TBSP for 8 servings); mash until smooth, adding splashes of reserved potato cooking liquid as needed. • Add half the parsley and season generously with salt; stir to combine.