Add garlic, brown sugar, soy sauce, red pepper flakes, salt and pepper, chicken broth, and olive oil to slow cooker. Stir thoroughly to combine.
Next, add chicken thighs to crockpot and coat with sauce. Cook on high for 4 hours, stirring occasionally. When there's ten minutes left of that cooking time, heat your oven's broiler.
Using slotted spoon, carefully remove chicken thighs and add to glass baking dish. Broil for 5-10 minutes or until tops are nicely browned.
Garnish with extra sauce from crockpot and fresh parsley. We recommend serving this on a bed of white rice and with some roasted veggies for a more complete meal.