"Now burn the ginger and garlic." I'm holding a phone in one hand and staring at the skillet in front of me trying to decide if my aunt, who is coaching me through making my very first pot of dal, is worth trusting on this. Burning your food is a sign you've gone to far, made a mistake, that you've done something wrong. But my Aunt Ginger (true story — her name is Ginger) sensed the hesitation in my silence and implored me to do as she instructed. So up the heat went, and the ginger and garlic were cooked until they were a deep, tawny brown.
Ginger's flavor undergoes numerous chemical changes depending on the type of heat applied to it. In the case of burning, which requires you to cook it until just before it blackens, the characteristic sting of ginger mellows into something heady and earthy. Bringing into the point right before burning adds a smoky element.
Similarly, the technique of charring ginger over an open flame or in your broiler works to lessen the burn while adding a smoky flavor. This is a key step in recipes like chicken tikka masala, which seek to bring the smoky flavors of a tandoori oven into the home kitchen. If you've made pho from scratch and skipped the charred onion and ginger step, you're missing out on the deep, smoky sweetness this technique brings.
Beyond chicken tikka masala and pho, you can use the technique of charring ginger and garlic to add a smoky sweetness to anything from pasta sauces and soups to dressings and marinades. I'm partial to adding it to a pot of beans for smoky complexity, or tossing it into dal, of course.