In a large mixing bowl, combine the whipping cream, sugar, and vanilla extract. Whip the cream on high speed until soft peaks form.
Add the powdered milk and continue whipping until the powder dissolves into the whipped cream and stiff peaks are formed. Do not overmix.
Refrigerate until ready to serve, up to 8 hours.
Notes
Use cold heavy cream. The colder the cream, the easier it will whip up. You could even try putting your bowl in the freezer for 30 minutes before you start as well.
Don't walk away if using a stand mixer! It doesn't take long to make your own whipped cream. So don't walk away or you might just skip past the whipped cream phase and end up with butter instead.
To freeze:Freeze leftover whipped cream in dollops on a lined tray. Once frozen solid, remove them to a ziptop freezer bag and store in the freezer until ready to serve. To use, just add one frozen dollop to your coffee or cocoa drink.