I found this wonderful recipe on Pinterest...it's gluten-free, light and rich so one cookie is very satisfying.
Flour-less Chocolate Passover Cookies
3 cups powdered sugar
2/3 cup cocoa powder
1/4 teaspoon salt
4 large egg whites, at room temperature
1 tablespoon vanilla extract
1 cup chocolate chips
1. Preheat oven to 350 degrees. Line two baking sheets with parchment paper.
2. On a large bowl whisk together the powdered sugar with the cocoa and salt. Whisk in egg white and vanilla extract and beat just until the batter is moistened. Gently stir in the chocolate chips.
3. Spoon batter onto the prepared baking sheets. Bake about 14 minutes until the tops are glossy and lightly cracked. Let cookies cool completely and store in an airtight container for up to 3 days.