Gently crush your cereal into coarse crumbs. You can put them in a sealed baggie and tap with a rolling pin, or use a food processor for quick results. Divide these crumbs evenly into two small dessert cups or jars (about 1/2 cup capacity each).
In a medium bowl, beat the softened cream cheese until it's super smooth and creamy.
Add 1/4 cup of the powdered sweetener to the cream cheese and beat until fully combined. Then, stir in the key lime juice. If you like a hint of green, add 3-4 drops of food coloring and mix until you achieve a very light, pleasing shade.
In a separate medium bowl, combine the heavy whipping cream with the remaining 1 tablespoon of powdered sweetener. Beat until the cream forms stiff peaks, meaning it holds its shape well.
Carefully fold most of the whipped cream into the key lime cream cheese mixture. This makes the cheesecake light and airy! Reserve about two tablespoons of whipped cream for a pretty topping later. Spoon the delightful cheesecake mixture over the cereal crumbs in your prepared jars.
Top each serving with the reserved whipped cream and, if you like, a thin slice of lime for garnish. Pop them in the fridge for about 30 to 60 minutes to let them set nicely. Then, dig in!