Ingredients:
- 1 lb ground beef (80/20 lean-to-fat ratio)
- 1/2 cup panko breadcrumbs
- 1/4 cup whole milk
- 1 large egg, beaten
- 1 tbsp Worcestershire sauce
- 1/4 cup yellow onion, grated
- 1 tsp Kosher salt
- 1/2 tsp cracked black pepper
- 1/2 tsp garlic powder
- 2 large yellow onions, thinly sliced
- 8 oz baby bella mushrooms, sliced
- 2 cups beef bone broth, low-sodium
- 2 tbsp all-purpose flour
- 2 tbsp unsalted butter
- 1 tsp Dijon mustard
- 2 lbs Yukon Gold potatoes, peeled and cubed
- 1/2 cup heavy cream, warmed
- 4 tbsp salted butter
Instructions:
- Prepare the panade by mixing panko breadcrumbs and milk in a small bowl until a paste forms. Let sit for 5 minutes.
- In a large bowl, combine the ground beef, panade, beaten egg, Worcestershire sauce, grated onion, salt, pepper, and garlic powder. Mix gently until just combined; do not overwork the meat.
- Shape the mixture into 15 small meatballs, roughly 35g each.
- In a large cast-iron skillet over medium-high heat, sear the meatballs until browned on all sides (about 6 minutes total, 3 minutes per side). Remove meatballs from the pan and set aside, leaving the rendered fat and browned bits (fond) in the skillet.
- While meatballs sear, boil the cubed Yukon Gold potatoes in salted water for 15 minutes until fork-tender.
- In the same skillet used for the meat, melt 1 tbsp unsalted butter. Add sliced onions and mushrooms. Sauté for 8 minutes until deeply caramelized and jammy, scraping the bottom of the pan to incorporate the fond.
- Sprinkle flour over the vegetables and cook for 2 minutes.
- Gradually whisk in the beef bone broth and Dijon mustard. Bring to a simmer until thickened.
- Return the meatballs to the gravy. Simmer for 10 minutes until thickened and velvety
- Drain the potatoes and pass through a ricer. Fold in 4 tbsp salted butter and warmed heavy cream until velvety. Season with sea salt to taste.
- Serve the meatballs and rich gravy generously over the silky mashed potatoes.