For tadka, green chilies can be either slit or chopped, depending on the desired level of heat and flavor distribution. Slitting releases a milder, more subtle heat, while chopping provides a more intense and even distribution of spiciness.
The decision to slit or chop green chilies for tadka largely depends on your personal preference for heat and how you want the chili flavor to infuse the dish.
Slitting: When you slit a green chili lengthwise, you create openings that allow the chili's oils and capsaicin (the compound responsible for the heat) to slowly release into the hot oil. This results in a milder, more nuanced heat that permeates the tadka without overpowering the other flavors. The chili itself remains relatively intact, providing a visual element to the dish.
Chopping: Chopping green chilies exposes more of the chili's surface area to the hot oil. This leads to a faster and more intense release of capsaicin, resulting in a spicier tadka. The chopped pieces also distribute more evenly throughout the dish, ensuring that each bite has a noticeable kick.
Consider the other ingredients in your tadka and the overall flavor profile you're aiming for. If you want a subtle warmth that complements the other spices, slitting is a good choice. If you're looking for a bold, spicy flavor, chopping is the way to go. You can also remove the seeds from the chilies to reduce the heat level, regardless of whether you slit or chop them.
Always add green chilies to the hot oil after the mustard seeds have spluttered and before adding other spices. This ensures that the chilies release their flavor properly without burning. Burning the chilies can result in a bitter taste.