Tadka, or tempering, is often the final step in Indian cooking because it infuses the dish with aromatic spices and enhances the overall flavor profile, adding a final layer of complexity and freshness.
Tadka involves heating oil or ghee and then adding whole spices, dried chilies, and sometimes aromatics like garlic, ginger, or onions. The hot oil extracts the essential oils from the spices, releasing their aroma and flavor. This infused oil is then poured over the dish, either at the end of cooking or just before serving.
Adding tadka at the end preserves the volatile aromatic compounds in the spices. If added earlier in the cooking process, these compounds would evaporate, diminishing their impact on the final flavor. The final tadka provides a burst of fresh, vibrant flavor that elevates the entire dish. It also adds a visual appeal, with the glistening oil and colorful spices creating an enticing presentation.
Be careful not to burn the spices during the tadka process. Burnt spices will impart a bitter taste to the dish. Keep the heat moderate and watch the spices closely, removing the tadka from the heat as soon as they release their aroma.