Start the oven at electrical heat at 175 Celsius degree.
Blend the biscuits in a blender to small crumbles.
Melt the butter in a sauce pan.
Mix the biscuits ant the melted butter in a big bowl.
Pour the biscuits in a baking form (with removable edges), and press into the base and up the sides of the baking form.
Put the bottom in the middle of the oven for 10 minutes.
While the bottom is in the oven prepare the rest of the pie
Separate the egg yellow from the white, and pour the yellow in to a bowl. Add the condensed milk, and the lime juice. Stir by hand for a few minutes (3-4 minutes) until the mixture becomes a little thicker.
Take out the bottom from the oven, and pour the mixture on the bottom.
Put the pie in to the middle of the oven for 15 minutes.
Take out the pie and let it cool down in room temperature.
Pour the whipping cream and a little vanilla sugar into a bowl, and Stir the whipping cream with an electrical mixer.
Put the whipping cream into a piping bag and sprits like a ring along the edges of the pie. If you have fresh lime fruits decorate the pie with thin slices for a nice touch.
Let the pie rest a few hours in the fridge before serving.