Foryoueats: Healthier Swedish Meatballs

1 tablespoon olive oil

½ sweet onion, grated

1 pound ground sirloin

8 ounces ground pork

¾ cup seasoned panko bread crumbs

1 egg

1 tablespoon milk

1 teaspoon garlic powder

1 teaspoon salt

½ teaspoon freshly ground black pepper

4 dashes Worcestershire sauce, divided

4 ½ cups reduced-sodium beef broth, divided

1 tablespoon reduced-sodium soy sauce

1 tablespoon finely chopped fresh rosemary

¼ cup cornstarch

⅓ cup Greek yogurt

2 tablespoons chopped fresh parsley

Healthier Swedish Meatballs