To steam the eggplant, fill a saucepan 1/4 full with water and bring to a slow boil on the stove top.
Line a bamboo steamer with parchment or baking paper. If you have stacked steamers, line both. If not, you'll need to cook the eggplant in batches unless you have a large steamer.
When the water has come to a boil, place the eggplant batons in to the steamers evenly (not stacked).
Steam for 10 - 15 minutes or until the eggplant is cooked through. To check, carefully press the sides, if they are soft the eggplant is ready.
While the eggplant is cooking place the yoghurt, lemon juice, garlic, 1/4 teaspoon ground cumin and a pinch of seat salt in a bowl and combine.
Taste and adjust seasoning.
Brush a tiny amount of olive oil on to one side of each of the pita breads.
In a small fry pan or skillet dry fry a portion of the cumin seeds for 30 seconds, add a small pinch of sea salt and finally press a pita bread down on to the pan for around 25 seconds. Repeat with the other pitas.
Place the pitas on a plate.
Using the same pan, add 1/2 teaspoon of olive oil, the remaining dried cumin and ground coriander.
Remove the cooked eggplant and toss (including the juices from the parchment paper) in to the spiced oil. Stir gently to coat and turn off the heat.
To serve, dollop a good amount of hummus on to each pita and spread.
Spoon the eggplant directly on top equally and drizzle with the yoghurt dressing.
Season again with a small amount of sea salt, sprinkle with mint and serve.