To make restaurant style kadai paneer with smoky flavors first you will have to saute onions and bell pepper in high flame as mentioned in the recipe. This alone will lend a mild smoky flavor to the dish. For furthermore smoky flavor you can do dhungar method. That is infusing charcoal smoke in the curry. To incorporate dhungar in this recipe heat a piece of charcoal until it is flaming hot. Place it carefully in a small bowl and place the bowl in the pan with curry. Add some oil or ghee to the hot charcoal and close the pan tightly. Let the flavor infuse for 3-4 minutes. Discard the charcoal with oil and serve the curry immediately.