For dal, the concept is simple - soak, cook, season. You can search the Internet and cookbooks and find a dal for every occasion. You can make it spicy or mild, thick or soupy, savory or sweet and sour. I've made dal hundreds of times. For example, The Dal House, Urad Dal Roti, and even Urad Dal Roti.
And dal doesn't need to be the final outcome. I make dal just to make dal patties. Inspiration came in the form of a couple of sweet potatoes. I love them and I knew they would add some sweetness to spicy dal. Together, they would make delicious patties.
For the dal I soaked the chana overnight, cooked it in plenty of water the next day until it was soft with a bit of tooth, then seasoned it gently with cumin, turmeric, garlic, ginger, etc. I roasted the sweet potato in the skin, removed the flesh and mixed it with the dal. In a separate small pan I heated mustard and cumin seeds in some oil until they sputtered. Then added a smashed cardamom pod, diced onion, chopped garlic and ginger, diced jalapenos, and garam masala (homemade), and salt. This cooked seasoning was where the flavor came from. I wasn't shy with these spices.
I added the cooked mixture to the dal/potato mixture until just combined then let it cool completely. To help bind it all I added an egg. It's still a soft mixture and isn't going to yield firm patties, like a hamburger. But that's not really the goal, at least not for me.
I refrigerated the mixture for about an hour before I shaped the patties. Just made it easier to work with. Before I shaped the patties I oiled my hands a bit. You can also use big spoons to shape patties, or a large ice-cream scope. Get creative.
I made round small chubby patties and I made oblong thinner patties. Shape is totally up to you.I fried these in a non-stick pan in olive oil, on medium heat, until they were crispy on each side. I served them with yogurt. I think I ate all of them in two days. I loved them.