In a saucepan, add 395g of condensed milk and 1 tablespoon of cornstarch. Mix well until starch dissolves.
Add 400ml of milk and 4 tablespoons of powdered chocolate. Turn on medium heat and stir until cream thickens. As soon as the cream thickens, add 200g of cream and stir for approximately 2 minutes. Remove pan from heat and set aside.
Soak the champagne biscuit in the milk.
In an ovenproof dish, make the first layer of biscuit and pour half of the cream on top. With a spoon, spread well and throw in chocolates to taste. Make another layer of biscuit and pour the rest of the cream on top. Spread well and place more chocolates on top of the cream.
Now refrigerate for approximately 4 hours.
Melt 150g of milk chocolate and add 200g of cream. Mix very well. Pour the ganache over the pave, spread and refrigerate again for 1 hour.
For decorating, I used sprinkles to taste, but you can decorate however you like.