Peel and finely dice the ginger. Thinly slice the onion. Cut the cauliflower into bite-size pieces, including the stem. Defrost the peas in a bowl with water, and then drain the peas.

In a wide pot, heat the oil over medium-high heat. Add the cumin and asafetida and cook for 30 seconds, stirring constantly. Add the ginger, coriander, chile, tumeric and cook for 30 seconds more.

Add the onion, lower the heat, and cook until limp, stirring occasionally, about 4 minutes. Next add the cauliflower and salt. Mix everything together, then pour in 1/2 cup water, cover the pot, and simmer until the vegetables are tender, about 10 minutes. Add the peas and cook for a few minutes more, until they're bright green. Add the amchoor powder and garam masala, stir together, taste for salt, and serve.