In a medium bowl, place 1 cup yellow split peas and about a cup and a half of water. Allow the split peas to soak for 30 minutes.
Once soaked, drain the split peas. Then add them to a large pot with about 8 cups of water and 1 tsp turmeric and bring the water to a boil. Boil for about 20-30 minutes until the split peas start to tenderize and break if you push one with your finger.
Drain the split peas, but reserve the cooking liquid. Set both in the fridge and allow them to cool completely.
While the peas are cooling, toast 1 tsp fennel seeds in a dry pan on the stove.
Add 2 cups + 6 Tbsp all purpose flour to a large bowl along with 1 tsp salt and mix to combine. Then add about ¾ cups of the reserved liquid to the flour and salt, little by little. Mix by hand, kneading until a soft dough forms, adding more water or flour as necessary. Cover and rest for 10-15 minutes.
Pulse the split peas in a food processor along with ½ tsp cumin and ½ tsp salt until they are very crumbly.
Separate the dough into 8 equal balls. Make a pocket in the middle of the dough balls. Add about 1-2 tablespoons of the crumbly split pea mixture, pressing it into the pocket to fill it. Reform the dough over the top of the split peas and seal the edges.
As you finish each dough ball, roll it in flour and set it aside while you make the rest.
Once the dough balls are all prepared, flour a work surface. Press each ball flat with your palm, then use a floured rolling pin to roll it as thin and round as possible (about ⅛” thick). Add more flour as necessary to keep it from sticking.
Heat a cast iron or griddle over medium heat and add a drizzle of oil. Place the dhal puri on the griddle, then brush the side that is up with oil. Keep the dough on the griddle for about one minute, then flip it and brush with oil again, cooking for one minute. One final time, flip it and allow it to cook for about one minute, or until the dough starts to puff up and cook through.
Serve and enjoy!