Soak the rice, urad dal and methi seeds for 3-4 hours or up to overnight. Together is fine.
Before making the kali, prepare the panavalla paakam if you haven't already--combine a block of jaggery with a cup of water and bring to a simmer on the stove. As the jaggery warms, it will be easy to crumble with a spoon. Once it's dissolved, continue to boil until you get a thick syrup. Don't worry too much about string-consistencies. Set aside.
Grind the rice-dal-methi mixture with just enough water to make a semi-fine paste.
The batter will be thick, so thin it with water until it is light and pours well. (Do not add too much water while grinding or it will be hard to get the right consistency. Get the batter to the right texture and then thin it). Thinning is important so that the batter doesn’t thicken too fast and catch at the bottom of the pan in the next step. Also, the rice in the batter needs water to cook properly!
Set the pan on a low flame and mix continuously—the mixture will thicken fast and get lumpy if it’s not continually attended to. I use a wire whisk at this stage.
When the batter thickens and starts to appear semi-cooked and a little glassy, add 1 tablespoon ghee—mix to incorporate—and then follow with 3 tablespoons sesame oil in 1-spoon increments. The batter will be a little “hydrophobic” and the oils will refuse to combine, so go slowly. Switching to a wooden spoon or spatula to mix in the fats makes it a little easier.
Slowly pour in the panavella paakam, a little at a time, again mixing slowly but constantly to incorporate.
The vendhaya kali is done when the mixture starts to look more glassy than chalky and when wet fingers leave small indents on the surface of the kali: the batter doesn’t stick to your fingers
Add the crushed cardamom.
Serve warm with more sesame oil drizzled over top and some more panavalla paakam on the side.
Toast the broken cashew pieces in a little ghee, if you're using, and scatter on top.