Briefly heating spices and dried chiles in oil or ghee allows their flavors to bloom, creating a flavorful tadka that serves as the backbone of this dish. It also adds a crispy, spicy finish to the creamy mixture of mung beans, lentils, and pigeon peas.
Tadka Dal
¾ cup dried moong dal (split yellow mung beans) (about 5½ ounces)
¾ cup dried masoor dal (split red lentils) (about 5 ounces)
¾ cup dried toor dal (split pigeon peas) (about 5¾ ounces)
2 ½ teaspoons kosher salt, plus more to taste
1 ½ teaspoons ground turmeric
6 to 7 cups water, divided
1 ½ tablespoons canola oil
4 green cardamom pods, crushed, shells discarded
4 whole cloves
1 ¼ teaspoons cumin seeds
1 medium-size yellow onion, finely chopped (about 2 cups)
2 medium-size fresh serrano chiles, stemmed, seeded if desired, and finely chopped (about 2 1/2 tablespoons)
1 medium tomato, chopped (about 1 cup)
¼ cup roughly chopped fresh cilantro, plus more for garnish
Roti
2 cups atta (Indian whole-wheat flour) (about 8 5/8 ounces), plus more for dusting
.75 to 1 cup water, divided
¾ teaspoon kosher salt
Melted ghee, for brushing
Tadka
3 tablespoons ghee
3 small dried chiles (such as Diaspora Co. Whole Sannam Chillies), or more to taste
1 teaspoon cumin seeds
Stir together moong dal, masoor dal, toor dal, salt, turmeric, and 6 cups water in a large saucepan; bring to a boil over medium-high. Reduce heat to medium-low; partially cover, and cook, stirring occasionally, until dal is soft and tender, 35 to 40 minutes. Add up to remaining 1 cup water, 1/4 cup at a time, until desired thickness and consistency is reached.
Stir together atta, 3/4 cup water, and salt in a medium bowl. Knead mixture in bowl until all dry flour is incorporated,adding remaining 1/4 cup water, 1 tablespoon at a time, if needed to incorporate flour. Transfer dough to a clean work surface; knead until stretchy and slightly sticky, 5 to 7 minutes. Shape dough into a ball, and return to bowl. Cover with a clean towel; let stand at room temperature until dough is smooth and matte, about 30 minutes.
Heat oil in a medium-size heavy-bottomed saucepan over medium. Add cardamom, cloves, and cumin; cook, stirring constantly, until fragrant, 30 to 45 seconds. Add onion and serrano chiles; cook, stirring often, until onion is lightly browned around edges, 5 to 8 minutes. Add tomato; cook, stirring often, until tomato begins to break down, 2 to 4 minutes. Remove from heat. Add tomato mixture and cilantro to dal mixture; stir to combine. Season to taste with salt. Cover and keep warm over low.
Once roti dough has rested, turn out onto a work surface lightly dusted with atta. Divide dough evenly into 16 pieces (about 1 ounce each). Working with 1 dough piece at a time and keeping remaining pieces covered with a towel, shape dough into a ball. Dust ball thoroughly with atta, and flatten slightly. Using a rolling pin, roll dough into a circle until uniformly thin and about 6 inches in diameter. Rotate the disk 90 degrees after each roll, flipping and dusting with atta occasionally to make a perfect circle. Repeat with remaining dough pieces.
Heat a large cast-iron skillet over high. Place 1 roti round in skillet; cook until bubbles start to form and bottom is speckled with brown spots, 30 to 45 seconds. Flip roti using tongs; cook until it puffs up completely and is evenly cooked on both sides, 30 to 45 seconds. (Small charred spots are delicious and totally OK.) If roti doesn't completely puff up, pat the top using a clean towel to encourage it to inflate. Remove roti from skillet, and brush both sides lightly with melted ghee; transfer to a serving plate. Repeat process with remaining roti rounds and ghee.
In a small skillet, heat ghee over medium-high. Add dried chiles and cumin to pan; cook, stirring occasionally, until cumin is toasted and fragrant, about 30 seconds. Divide dal mixture among bowls, and drizzle each portion with desired amount of warm tadka. Sprinkle with additional cilantro, and serve alongside hot roti.
