Add 1 tsp of unflavored gelatin powder and 1 tbsp of cold water to a small bowl. Stir to mix well, set aside and let bloom for 3 minutes.
Pour 1 cup of heavy whipping cream to a large mixing bowl, keep it in the fridge for now. Pour ¼ cup of heavy whipping cream to a small size bowl.
Pour boiling water to 2 medium bowls until they are half full.
Place the 2 small bowls (one with gelatin mixture, the other with heavy whipping cream) into the 2 medium bowls, so that the small bowls are sitting into hot water.
Use 2 spoons to stir the gelatin mixture and the heavy whipping cream, so that they are heated evenly.
When the gelatin mixture is fully melted into liquid, pour the warmed heavy whipping cream into the gelatin bowl. (Touch the heavy whipping cream with a finger, it should feel similar to your body temperature. ) Stir until well combined. Take the small bowl out from the hot water bath, set aside on the countertop.
Take the large mixing bowl with the large portion of heavy whipping cream out from the fridge, add powdered sugar and vanilla extract to the heavy whipping cream.
Use the beater of your hand mixer to gently stir the heavy whipping cream until the powdered sugar is roughly dissolved. (In this way, the powdered sugar won't splash out when you whip the cream at the next step.)
Beat the heavy whipping cream with a hand mixer on medium speed for about 5 minutes until soft peaks form. (Lift the beater and cream will drop off like melted ice cream. Just starting to see trails of cream, but they will gradually dissolve.)
Pour the gelatin cream mixture to the mixing bowl, continue to beat the cream until your desired whipping stage. (*See Note)