Blend the strawberries and condensed milk. You can use an immersion blender, a countertop blender, or a food processor.
Whip the cream to soft peaks. Use a stand mix, handheld mix or a balloon whisk (which will take a bit longer).
Add the strawberry-condensed milk mixture 1/3 at a time into the whipped cream, folding gently with a spatula.
Transfer the mousse to six serving containers (like ramekins, dessert glasses, cocktail glasses).
Cover and refrigerate for at least 2 hours but preferably overnight.
Serve with fresh strawberries on top.
