Step 1: Sear the Steak Tips (Optional but Recommended)
Pat the steak cubes completely dry with paper towels. Season generously with salt and pepper. Heat the oil in a large skillet or Dutch oven over medium-high heat. Working in batches to avoid overcrowding, sear the steak cubes on all sides until a deep brown crust forms, about 2-3 minutes per side. This step is not strictly necessary but adds immense flavor. Transfer seared beef to the slow cooker insert.

Step 2: Whisk Together the Teriyaki Sauce
In a medium bowl, whisk together the soy sauce, brown sugar, honey, rice vinegar, beef broth, minced garlic, grated ginger, black pepper, sesame oil, and sriracha (if using) until the sugar is mostly dissolved.

Step 3: Combine and Cook
Pour the teriyaki sauce mixture over the steak tips in the slow cooker. Stir gently to coat the meat. Cover and cook on LOW for 6-7 hours or on HIGH for 3-4 hours. The meat is done when it is fork-tender. Avoid overcooking on HIGH, as it can make the meat dry and stringy.

Step 4: Thicken the Sauce
About 30 minutes before serving, skim off any excess fat from the surface of the liquid. In a small bowl, make a slurry by mixing the cornstarch and cold water until smooth. Turn the slow cooker to HIGH if it was on LOW. Stir the slurry into the cooking liquid and beef. Replace the lid and cook for an additional 20-30 minutes, or until the sauce has thickened to a glossy, gravy-like consistency that coats the back of a spoon.

Step 5: Add Vegetables (Optional)
If adding quick-cooking vegetables like broccoli florets or snap peas, stir them into the pot during the last 20-30 minutes of cooking (after adding the slurry) to steam until tender-crisp.

Step 6: Rest and Garnish
Once the sauce is thickened, turn off the slow cooker. Let the steak tips rest in the sauce for 10-15 minutes; this allows the meat to reabsorb some juices and the flavors to settle. The sauce will continue to thicken slightly as it cools.

Step 7: Serve and Enjoy
Serve the tender teriyaki steak tips and sauce directly over a bed of hot, steamed rice. Garnish generously with sliced green onions and a sprinkle of toasted sesame seeds. Offer lime wedges on the side for a bright, acidic squeeze if desired