Start by melting high-quality dark chocolate with milk, sugar, and cornstarch in a saucepan. Whisk until smooth and thickened, then transfer to a bowl. Chill for at least 2 hours.

Once your pastry cream is cool, gently fold in mascarpone cheese and vanilla extract. Mix until well combined, ensuring a velvety texture. If the mixture is too thick, add a little heavy cream to lighten it.

In a separate bowl, beat the heavy cream until stiff peaks form. This step is optional but adds a delightful airiness to your tiramisu.

Dip ladyfingers briefly in coffee or chocolate milk and layer them in a baking dish. Spread a layer of chocolate pastry cream over them, then repeat the process until all ingredients are used. Refrigerate for 3-4 hours or overnight.

For a unique twist, layer the dipped ladyfingers in individual glasses with alternating layers of pastry cream and whipped cream. Chill the glasses in the fridge for 3-4 hours or overnight.

Just before serving, add a sprinkle of chocolate shavings or cocoa powder on top to enhance presentation and flavor.