Preheat the oven 450°F. Spray a 12-cup mini-muffin pan with cooking spray and set aside.
Place the eggplant on the grate of a gas burner over a high flame. Char the eggplant, turning it every few minutes, until the ski is blackened and the flesh is cooked through; this should take about 12 minutes. (Alternatively, you can char the eggplant on a barbecue grill, a grill pan or on a baking sheet under the broiler.)
Allow the eggplant to cool slightly, and then cut it in half. Scrape out the flesh, being careful not to incorporate the skin. Measure out 1/4 cup of the flesh; reserve the remaining eggplant for another use.
In a blender, combine the cooked eggplant, chicken broth, onion, garlic and egg white. Purée until smooth.