Start by crushing the corn starch biscuits into crumbs.
Transfer the biscuit crumbs to a bowl and add the melted unsalted butter. Mix very well and set aside.
Grease a medium baking tin with butter. Grease the sides and the bottom of the tin.
Line the whole baking tin with parchment paper, so you can easily unmold the dessert.
Pour all the biscuit crumbs into the tin and push them down lightly to form a base for the dessert, make it as flat as possible and set aside.
Chop the Brazil nuts into smaller pieces and set aside.
Now, put the white chocolate in a bowl, take it to the microwave and melt it in 30-second intervals or in a double boiler.
Add the condensed milk and the chopped nuts to the chocolate, mix very well until combined.
Pour this mixture over the biscuit base and spread evenly, making it as flat as possible.
Leave in the fridge for 2 to 4 hours.
After this indicated time, unmold and unwrap all parchment paper.
Serve.