Preheat oven to 450* F.
Cut Japanese eggplant into four pieces (half lengthwise, then cut those halves in half.) Toss eggplant and carrots with a tablespoon or two of olive oil, salt, and pepper on a baking sheet.
Roast eggplant about 15 minutes, then add cumin seeds and continue roasting until eggplant and carrots are tender, another 5-10 minutes. Remove from oven and let cool slightly.
In a food processor, combine garlic, sour cream, harissa, and spices. Add salt and pepper to taste. When cool enough to handle, add eggplant and carrots. Process until very smooth.
Serve warm or chilled as a dip with pita chips or fresh vegetables.