For the mashed potatoes
01 -
2 lb (900 g) russet potatoes, peeled and cut into 1 1/2-inch chunks
02 -
1 1/2 teaspoons kosher salt, plus more for the water
03 -
4 tablespoons (56 g) unsalted butter
04 -
1/2 cup (120 ml) whole milk, warmed
05 -
1/4 cup (60 ml) sour cream
06 -
Black pepper, to taste
For the meatballs
07 -
1/2 cup (35 g) panko breadcrumbs
08 -
1/2 medium yellow onion, grated
09 -
1 lb (450 g) ground beef, 85 percent lean
10 -
1 large egg
11 -
2 cloves garlic, minced
12 -
1 tablespoon ketchup
13 -
2 teaspoons Worcestershire sauce
14 -
1 teaspoon Dijon mustard
15 -
3/4 teaspoon kosher salt
16 -
1/2 teaspoon black pepper
17 -
1 tablespoon olive oil
For the mushroom gravy
18 -
2 tablespoons (28 g) unsalted butter
19 -
8 oz (225 g) cremini mushrooms, sliced
20 -
1/2 medium yellow onion, thinly sliced
21 -
1 clove garlic, minced
22 -
2 cups (480 ml) low-sodium beef broth
23 -
2 tablespoons all-purpose flour
24 -
3 tablespoons cold water
25 -
1 teaspoon Worcestershire sauce
26 -
1 teaspoon Dijon mustard
27 -
1 tablespoon chopped parsley, for serving