Delicious, served over mashed potatoes and gravy!

- 2 tbsp olive oil
- For the Meatballs:
- 1 cup breadcrumbs, regular, Panko or GF
- 1/4 cup milk or water
- 1½ lb lean ground beef
- 1 egg
- 1/2 cup diced onions
- ¼ cup (4 tbsp) ketchup
- 1 tablespoon dry mustard
- 1 tbsp Worcestershire sauce
- 1 tsp Kosher salt
- 1 tsp ground black pepper
- For the gravy:
- 2 tbsp butter
- 1 large onion, chopped
- 8 oz cremini mushrooms, sliced
- 1 tbsp Worcestershire sauce
- 1 cup unsalted beef broth
- 2 tbsp cornstarch
- salt and ground black pepper, to taste
- Optional garnish
- chopped fresh parsley