Season the beef chuck chunks generously with salt and pepper on all sides.

Add the seasoned beef to the slow cooker, then layer sliced onions, minced garlic, and grated ginger on top.

Pour in the beef broth and water, followed by soy sauce, sesame oil, and brown sugar. Stir gently to combine all ingredients.

Cover and set your slow cooker to low for 8 hours or high for 4 hours.

Cook until the beef is tender and easily shredded with a fork, and the broth is richly flavored.

About 10 minutes before serving, cook the ramen noodles in a separate pot according to package instructions. Drain and set aside.

Stir the baby spinach into the slow cooker just before serving, allowing it to wilt slightly in the hot broth.

Divide the cooked noodles among serving bowls, then ladle the beef and broth over the top.

Garnish with sliced green onions and optional soft-boiled eggs. Serve with sriracha or chili oil on the side for guests to add as desired.