Marinate the chicken pieces with ginger paste, garlic paste, a dash of lemon juice and some salt and keep aside.
While the chicken is in the marinade, finely chop the onions, tomatoes, coriander leaves and green chillies (discard the seeds of the chillies).
Place a grill pan or any non stick frying pan over heat and when it is more or less hot, place the chicken pieces. Drizzle half a tbsp of mustard oil. Let the chicken pieces grill over moderately high heat. It does not take long for boneless chicken to cook. We just need to roast it a bit over high heat to bring some charred colour to it.
When done, use a slotted spoon and take the chicken pieces out and place them in a mixing bowl.
Add the onions, tomatoes, green chillies, salt (if required) and juice of half a lemon. Add the coriander leaves too.
Now go back to your grill pan where there are chicken bits stuck to it. Add the rest of the mustard oil and turn on the heat.
When it becomes a little hot, add the fenugreek seeds. Let the seeds brown in the mustard oil and then turn off the heat.
Using a strainer, pour this oil into the chicken sadeko. If you like the taste of fenugreek seeds, you need not strain it too.
Check the seasoning and serve it with some lemon wedges.