The secret to a well-balanced pappu (dal) where the vegetable flavor shines is to add the vegetable towards the end of the cooking process and avoid over-spicing, allowing the vegetable's natural taste to remain prominent.
Achieving a pappu where the vegetable flavor is distinct involves a few key steps. First, choose a dal that complements the vegetable. Toor dal (split pigeon peas) is a common choice and works well with many vegetables. Second, cook the dal until it's soft and mushy, but not completely disintegrated. This provides a good base without overpowering the vegetable. Third, and most importantly, add the vegetable in the last 15-20 minutes of cooking. This prevents the vegetable from becoming overcooked and losing its flavor. For example, if using tomatoes, add them after the dal is cooked and simmer until they soften and release their juices. If using spinach, add it even later, just until it wilts. Finally, use spices sparingly. A simple tempering of mustard seeds, cumin seeds, and a pinch of asafoetida (hing) is often enough. Avoid adding too much chili powder or garam masala, as these can mask the vegetable's delicate flavor. Adjust salt to taste, keeping in mind that the vegetable itself will contribute to the overall flavor profile.
Don't be afraid to experiment with different vegetables! While tomato and spinach are common, try using bottle gourd (lauki), drumsticks (moringa), or even fenugreek leaves (methi) for unique and flavorful variations of pappu.