Slice the bananas thinly.
Put the whipping cream in a bowl and whip until stiff peaks form.
In another bowl, mix together the condensed milk, milk, and vanilla extract.
Add the mascarpone cheese and mix until smooth.
Gently fold the whipped cream into the cheese mixture.
In a glass cup, layer vanilla wafers, banana slices, and cream in that order.
Repeat the layers and cover the top with cream.
Chill in the refrigerator for at least 2 hours before serving.