Per 3⁄4 cup mousse
3 large bananas, mashed
2 cups whipping cream
3 tablespoons powdered sugar
2 tablespoons lemon juice
1⁄4 teaspoon (or to taste) ground nutmeg
1 tablespoon rum
Purée the bananas in a blender. Whip the cream at medium-high speed until it forms high peaks. Add the powdered sugar and whip briefly until it forms soft peaks (the mixture should be light and fluffy).
Fold the whipped cream into the mashed banana. Carefully stir in the lemon juice, nutmeg, and rum. Spoon into parfait glasses.