For the strawberry buttermilk mousse, soak the gelatin in cold water. Puree the prepared strawberries with the sugar and buttermilk.
Warm a few tablespoons of the strawberry buttermilk mixture, squeeze out the gelatin, dissolve it in the mixture and then stir it into the remaining mixture. Fold in the whipped cream.
Provide 7 ramekins and place a cookie (of choice) in each. Spread the strawberry-buttermilk mixture evenly and chill for at least 2 hours.