2 (3.5-ounce) packages instant ramen noodles, flavor packets discarded
1/3 cup beef stock
1/4 cup oyster sauce
1 tablespoon rice wine vinegar
1 teaspoon Sriracha, or more, to taste
1 tablespoon toasted sesame oil
1 pound lean ground beef
1 cup diced sweet onion
3 cloves garlic, minced
1 tablespoon freshly grated ginger
2 green onions, thinly sliced
1/2 teaspoon toasted sesame seeds
In a large pot of boiling water, cook ramen noodles until tender, about 3-4 minutes; rinse with cold water and drain well.
In a medium bowl, whisk together beef stock, oyster sauce, rice wine vinegar and Sriracha.
Heat sesame oil in a large skillet over medium heat. Add ground beef and onion, and cook until beef has browned, about 3-5 minutes, making sure to crumble the beef as it cooks; drain excess fat.
Stir in garlic and ginger until fragrant, about 1 minute.
Stir in beef stock mixture, scraping any browned bits from the bottom of the skillet.
Stir in ramen noodles until heated through and evenly coated in sauce, about 1-2 minutes.
Serve immediately, garnished with green onions and sesame seeds, if desired.