To prepare sheet pan eggplant, preheat the oven at 180C.
Slice off the crown of the eggplant.
Cut into 1/2 inch thick slices and chop each slice into 4-6 pieces.
Place the chopped eggplant on the sheet pan / baking tray.
In a small pan, heat the oil and fry the mustard and cumin seeds.
Once the seeds splutter, turn off flame and stir in spice powders and salt.
Transfer this oil with spices over the eggplant and gently rub the spice mix over all the pieces to coat well.
Pour 1/3 cup hot water in the middle of the sheet pan.
Using a thick aluminium foil, wrap the pan from end to end so that it is covered well. This helps generate steam from the water used so that the eggplant cooks fast and remains moist.
Carefully slide the sheet pan into the preheated oven and bake for 20-25 minutes at 180C until the eggplant pieces are soft.
Garnish with fresh coriander and serve hot.