Beat whipping cream, sugar, and vanilla until soft peaks form.
Add in mascarpone cheese and combine until stiff peaks form.
Quickly dip ladyfinger in coffee, then layer the bottom of a glass baking dish with ladyfingers.
Spread 1/2 of heavy cream mixture evenly on top of the ladyfingers. Repeat process with the second layer of ladyfingers and cream mixture.
Using a strainer, dust the top of your tiramisu with cocoa powder. Cover and refrigerate overnight.
Slice and serve!