Beat the heavy cream in a large bowl with an electric mixer at medium-high speed until it holds stiff peaks. Add the condensed milk, passionfruit puree and vanilla and beat until combined. Spoon the mousse into two 10- to 12-ounce bowls. Cover the bowls with plastic wrap and refrigerate until the mousse is firm, at least 2 hours. If you have access to a fresh passionfruit, spoon a little of the fresh fruit on top. The mousse is also delicious with some granola sprinkled on top.