Preheat the oven to 150°C / 300°F / Gas mark 2.
Line a baking sheet with greaseproof paper and set aside.
In a large bowl, sift together the cocoa, flour, cinnamon, salt and set aside.
Using your food processor, combine the butter, sugars, and vanilla. Mix on a medium speed for 3 to 5 minutes or until it turns light and fluffy.
Add the egg white and mix well. Add the flour mixture into the food processor and combine.
Take the mixture out of the food processor and form into a ball, cover tightly with plastic wrap, and refrigerate for 15 to 20 minutes.
Using a teaspoon, scoop the mixture into cookie portions and drop onto the baking sheet.
Flatten gently with the palm of your hand to make round cookie shapes.
Repeat until you have used up the mixture.
Bake for 10 to 12 minutes the remove to a cooling rack.
When cool, spoon about a tablespoon of the ice cream on the flat side of the cookie and top with a second cookie.
Serve or freeze for up to 1 week.