In a small bowl, whisk together balsamic vinegar, soy sauce, brown sugar, maple syrup, ketchup, Sriracha sauce, ginger, onion powder, half of the black pepper, and garlic powder. This sauce will be the heart of your dish, so ensure everything is well combined and flavorful.
Chop the green onions and set them aside for garnishing later. Their fresh taste will add brightness to the finished dish.
Season the chicken thighs with salt and the remaining black pepper. Make sure to coat the chicken evenly; this will enhance the flavor as it cooks.
Place the seasoned chicken thighs in the slow cooker. Arrange them in a single layer for even cooking.
Pour the prepared sauce over the top of the chicken. Make sure each piece is coated well in the delicious mixture.
Cover the slow cooker and cook on high for 2 hours or on low for 4 hours. The chicken is done when it is no longer pink and easily shreds with a fork.
Once the chicken is cooked, scoop the sauce out of the slow cooker and transfer it to a small saucepan. This will be used to thicken and finish the sauce.
In a separate bowl, whisk together cornstarch with a little cold water until dissolved. This will help thicken the sauce, giving it a luxurious texture.
Pour the cornstarch mixture into the saucepan with the sauce and heat over low. Stir continuously for about 5 minutes until thickened. The sauce should be glossy and able to coat the back of a spoon.
Drizzle the thickened sauce over the cooked chicken. Garnish with the chopped green onions and a sprinkle of sesame seeds for added flavor and visual appeal.
