Bring to a boil then reduce to a simmer. Cook until the rice has absorbed nearly all of the water.
Add the milk in two equal parts, bringing the liquid back to a simmer and cooking until nearly all of the milk has been absorbed before adding more milk. Stir frequently.
Add the vanilla extract with the last addition of milk. Cook until all of the liquid has been absorbed.
Remove the porridge from the heat and allow to cool slightly before packing for refrigeration. Chill completely (1-2 hours).
Assembly:
Combine the powdered sugar and heavy whipping cream.
Whip on medium-high until stiff peaks form.
Using a spatula, fold the whipped cream into the cooled porridge.
Top with a fruit sauce or compote immediately before serving.
Notes
Working ahead: You can make the porridge up to 3 days in advance.
Whipping heavy cream: Whip your heavy cream until it just begins to hold stiff peaks. You'll want to watch it carefully once it hits soft peaks as it will go from soft to stiff quickly.
Fixing broken whipped cream: If you've overwhipped your cream and it's broken (it'll look separated and chunky), you can fix it by drizzling cold, unwhipped heavy cream into it with your mixer on low. Keep adding cream and mixing until it's fluffy.
Storage: Will keep in the refrigerator for 2-3 days.