Add the cold water to a small bowl, then sprinkle the gelatin over it. Allow to sit for about 10 minutes, until it has set.
In a small skillet, add about 1/2-inch of water, and heat over medium-high heat. Place the small bowl with the gelatin directly inside the skillet. Stir the gelatin until it is melted, about 2 minutes. Remove the bowl from the skillet.
In the mixer, use whisk attachment and beat the heavy cream & powdered sugar. Beat on high to soft peaks. Add in the melted gelatin mixture and continue to beat until stiff peaks have formed.
Pipe the cream into the centers of the cupcakes using a pastry bag.