Pour cream into a bowl and add icing sugar. Whisk until stiff peaks and then transfer to a piping bag.
Fill a second piping bag with the dulce de leche. It will be much easier to layer!
Remove the skin from bananas and slice into rounds.
Now to assemble: take your serving glass and pipe in a thin layer of cream. Shake the glass side to side to spread the cream evenly across the bottom. Top with two Biscoff cookies (you may need to break them to make them fit).
Pipe on a thin layer of dulce de leche, and then 5-6 slices of banana. Repeat in this pattern until you’ve reached the top of the glass. Your final layer should be cream.
Complete all four glasses. Cover each with plastic wrap and place into the fridge for 8 hours, ideally overnight.
To serve, grate dark chocolate on top. Biscuits will have softened and the result is the most delicious pudding-style banoffee dessert.