Adjust the oven rack to the middle position and turn broiler on high heat. Line a cookie sheet with aluminum foil.
Prick eggplants several times with a fork and place them on the lined cookie sheet. Broil, turning every 5 minutes or so, until eggplants are browned and shriveled on all sides, approximately 10-20 minutes depending on size.
Do not remove from oven. Turn broiler off and heat oven to 375 degrees. Roast eggplants until they are very soft, approximately 20-30 minutes. Cool until easily handled.
While eggplants are cooling mix tahini, lemon juice, minced garlic salt and cumin in a medium bowl.
Split the eggplants, drain excess liquid, scrape out the flesh and add to tahini mixture. Be sure to reserve some of the liquid for later.
Mash and mix with a fork until well combined. Serve room temperature. Can be stored in an airtight container and refrigerated for up to 5 days.