Split the vanilla bean and scrape out the seeds.

In a large bowl, whisk the egg yolks, sugar, and vanilla seeds until the mixture becomes light and creamy.

In another bowl, mix the mascarpone with the lemon juice until smooth.

Add it to the egg yolk mixture and whisk until well combined.

In a clean bowl, beat the egg whites until stiff peaks form.

Gently fold them into the mascarpone mixture.

Do not overmix.

Mix the coffee and apple cider vinegar in a shallow bowl.

Dip each ladyfinger into the coffee mixture for 1 to 2 seconds.

Do not soak them.

Arrange half of the soaked ladyfingers in the bottom of a serving dish.

Spread half of the mascarpone mixture on top.

Add the remaining ladyfingers, then spread the rest of the mascarpone mixture over them.

Smooth the top and dust with cocoa powder.

Cover and chill for at least 4 hours before serving.