Cut eggplant in half lengthwise. With a spoon, carefully scoop out the flesh making sure not to pierce the eggplant skin. Set the eggplant shells aside. Dice the eggplant flesh.

In a large bowl, mix the eggplant flesh, tomato, feta cheese, garlic powder, olive oil, sea salt, and black pepper.

Fill in the eggplant boats with the vegetable mixture.

Arrange the eggplant boats in a 4- to 6-quart slow cooker in a single layer. Cover and cook on LOW for 4 hours.

Drizzle the yogurt over the eggplant boats. Garnish with the parsley and serve.