Add heavy whipping cream and instant coffee to a mixer and beat until combined well, about a minute.
Add mascarpone cheese, powdered sugar, and vanilla extract to the mixture. Beat on low until all ingredients are combined.
Increase speed to high and beat for an additional 3-5 minutes until stiff peaks form.
Pour tiramisu dip into a serving bowl and sprinkle top with cocoa powder before serving.
Refrigerate, covered, until ready to serve.
Notes
Serve dip with ladyfingers, vanilla wafers, or chocolate rolled cookies. Fruits, like apples and strawberries, are also a great idea. Instant coffee (not regular coffee) must be used. Decaf is fine.