Bring water to boil. Steam the carrots for around 2 minutes. It should be just soft not mushy.
Repeat for green beans as well. It took me about 3 minutes. Depending on how fresh and how small you cut them, the amount of time to steam them would vary but shouldn't take you more than 5 minutes each. Overcooking depletes the nutrients as well, not to talk about affecting the texture of the vegetables.
Heat 2 tsp of Extra Virgin Coconut oil
(or any oil of your choice) and when hot, add the mustard seeds. When it stops popping, add the asafoetida and urad dal. Add the chilli if using, at this point.
When it starts turning color, add the veggies. If using onion, add it after tempering (and before adding veggies). Once its soft add the veggies. Give it a quick stir along with turmeric and salt. This stir fry process is quick and shouldn't take more than 5 minutes since the veggies are already cooked.
After about 20 seconds, add the coconut if using. Toss, do a taste test and season if needed. You can add the sambar powder
now if using (before adding coconut). Add the curry leaves, stir and switch off heat.