2Crush cookies — Crush the cookies into fine crumbs. Add the melted butter and mix until the texture resembles wet sand.
3Press the crust — Pour the mixture into a tart pan or a 20 cm (8-inch) pastry ring. Firmly press the mixture into the bottom and up the sides using the back of a spoon or a glass.
4Chill the crust — Refrigerate for 30 minutes.
5White Chocolate Ganache
6Chop white chocolate — Finely chop the white chocolate and place it in a bowl.
7Heat the cream — Heat the heavy cream until it just begins to simmer, then pour it over the chocolate.
8Stir the ganache — Gently stir from the center outward until the ganache is completely smooth.
9Pour the ganache — Pour the ganache over the chilled cookie crust.
10Set the layer — Refrigerate for 45 minutes to 1 hour, until the surface is firm enough to support the next layer.
11Milk Chocolate Ganache
12Chop milk chocolate — Finely chop the milk chocolate and place it in a bowl.
13Heat the cream — Heat the heavy cream until it just begins to simmer, then pour it over the chocolate.
14Rest and stir — Let it sit for 1 minute, then stir until smooth and glossy.
15Pour the ganache — Carefully pour the ganache over the set white chocolate layer.
16Chill the layer — Refrigerate again for 45 minutes to 1 hour.
17Dark Chocolate Ganache
18Chop dark chocolate — Finely chop the dark chocolate and place it in a bowl.
19Heat the cream — Heat the heavy cream until it just begins to simmer, then pour it over the chocolate.
20Finish the tart — Carefully pour the ganache over the milk chocolate layer. Refrigerate until fully set before serving.