Heat 1 tbsp oil in pan/kadai on medium heat, once hot add the mustard seeds and allow them to pop.
Add in fenugreek seeds, cumin seeds, urad daal and mix, let the daal turn light golden in color.
Add in asafoetida, curry leaves, onions and tomatoes and allow them to soften a bit; once they are soft.
Add in the salt, turmeric powder, red chili powder and sambar powder or garam masala whichever you prefer; mix well.
Add in the tomato sauce, tamarind paste and allow it to come to a boil. Taste and adjust the salt.
Add in the brussels sprouts and mix well but gently.Cover and allow them to cook stirring periodically.While stirring if you feel that they are drying up and burning, sprinkle some water, mix, cover and cook. (Note: The total cooking time varies because of the size of the pieces, it may take between 15-20 minutes to cook)
Once done, take off the flame and serve hot.