In a pan over medium heat, dry roast the dals, coriander seeds and dry red chilies.
Once they turn slightly aromatic, add the other seeds and curry leaves and continue roasting them until they're aromatic.
Take the pan off heat and once everything has cooled down, transfer to a blender jar. Add the asafoetida and turmeric too.
Blitz everything for a few minutes until you get a fine powder.
Notes
Make sure you keep the heat low while roasting the spices. You don't want them to burn.
Depending on your personal preference, you can grind the mixture into a smooth powder (like I did with my Peri Peri seasoning) or keep it slightly chunky (like my Egyptian Dukkah).
You can also sieve the mixture through a fine mesh sieve if you want that smooth texture.
Also keep stirring frequently while the spices are roasting- that way, they'll become nice and toasty on all sides.
You can also choose to roast all the spices and dals separately, one at a time if you want to.
Use any good quality non-stick pan to roast the spices.
Make sure you allow the roasted spices to cool down completely before you blitz them. This will ensure you get a fine powder, and not a mixture that's clumped together.