Step 1

MIX: In a medium bowl, combine the grated onions, panko breadcrumbs, 3/4 teaspoon kosher salt, and all the remaining ingredients except the ground beef and oil. Allow the mixture to stand for 5 minutes so that the excess liquid from the onions gets soaked up by the breadcrumbs. Then, add the meat and mix until *just* combined. Divide the meat mixture into 18-22 meatballs that are 1 1/2 tablespoons each.

Step 2

COOK: Add the tablespoon of oil to a large skillet and let it heat through on medium-high heat. When hot, add the meatballs in a single layer, do this in batches if the pan is not large enough. Cook the meatballs for 6-9 minutes, flipping halfway through until all sides brown evenly, don’t worry if they aren’t cooked all the way through. Remove to a plate. Add additional oil and cook any remaining meatballs the same way.

Step 3

GRAVY: Add 1 tablespoon of butter to the skillet and allow it to melt. When melted, add the mushrooms and allow them to cook and brown, about 3-4 minutes. When brown, add the onions and saute for 3 minutes before adding in the garlic. Let the garlic cook for 30 seconds or until fragrant. Then add the remaining butter to the skillet and allow it to melt. When melted, add the flour and stir to combine. Allow the flour to cook for 1 minute, stirring constantly. Gradually pour in the beef stock with one hand while you stir with the other hand. Then, stir in the Worcestershire sauce, mustard, and soy sauce. Allow the sauce to cook and simmer, once simmering, let cook for 3 minutes or until it thickens just a bit. Then add the meatballs to the skillet (with any released juices that may have collected on the plate) and let cook for 4 minutes. If the gravy thickens too much, you can add a splash of water to thin it to your liking. Taste and adjust seasonings as desired. Serve meatballs and gravy over mashed potatoes or egg noodles!