Add the beef stew meat, carrots, onion, garlic, ginger, beef broth, and soy sauce to the slow cooker. Stir to combine.
Cover and cook on low for 7 to 8 hours until the beef is fork-tender.
In a small bowl, mix the cornstarch with 2 tablespoons of the cooking liquid until smooth. Stir this mixture back into the stew.
Turn the slow cooker to high, cover, and cook for 15 more minutes until the broth thickens slightly.
Turn off the heat and stir in the sliced scallions just before serving.