Rinse the split yellow lentils (dhal) and soak them in water for 30 minutes.
Drain the lentils and transfer them to a blender or food processor. Add cumin seeds, mustard seeds, onion, garlic, turmeric, coriander, cumin, and salt. Blend into a smooth paste, adding water as needed to achieve the desired consistency.
Heat 2 tablespoons of vegetable oil in a pan over medium heat. Pour the lentil mixture into the pan and cook, stirring frequently, for 10-15 minutes until the mixture thickens.
Divide the dough into lime-sized balls. On a lightly floured surface, use a rolling pin to roll each ball into a thin round disc.
Heat a skillet or griddle over medium heat. Add a small amount of vegetable oil and cook the dhal puri on both sides until golden brown and puffed up.
Serve the dhal puri warm, with your favorite accompaniments.
