1. Prepare Beef and Combine Sauce Ingredients:

• Slice the flank steak thinly against the grain into bite-sized strips.
• In the insert of your slow cooker, combine the sliced beef, soy sauce, packed brown sugar, beef broth, minced garlic, and grated fresh ginger.
• Stir everything together well to ensure the beef is evenly coated with the sauce ingredients.

2. Slow Cook:

• Place the lid securely on the slow cooker.
• Cook on the LOW setting for 4-5 hours OR on the HIGH setting for 2-3 hours. The beef should be tender when done. (Note: Flank steak is lean and cooks relatively quickly; avoid overcooking, especially on high, to ensure tenderness).

3. Add Broccoli and Thicken Sauce (Optional):

• About 30 minutes before the end of the cooking time, add the broccoli florets to the slow cooker on top of the beef mixture. Stir gently if needed to submerge some pieces. Replace the lid and continue cooking.  
• Optional Thickening: If you desire a thicker sauce, prepare the cornstarch slurry by whisking 1 tablespoon of cornstarch with 2 tablespoons of cold water in a small bowl until smooth. Stir this slurry into the liquid in the slow cooker during the last 15-20 minutes of cooking (after adding broccoli). The sauce will thicken as it simmers.

4. Serve:

• Once the cooking time is complete, the beef should be tender, and the broccoli should be tender-crisp. Give the mixture a gentle stir.
• Serve the Slow Cooker Beef and Broccoli hot over cooked rice.
• Garnish generously with sesame seeds before serving.