Whisk heavy cream and mascarpone cheese in a large mixing bowl until combined.
Add icing sugar gradually while whipping followed by ⅔ cup of coffee and vanilla extract. Whisk together until you achieve a soft peak.
Seal the bowl with plastic wrap and place move to refrigerator.
Layer the base of your jars with crumbled chocolate cake. Press the cake into the base of the jars with a spoon. Drizzle the remaining ⅓ cup of coffee onto the cake.
Top a generous serving of the cream, mascarpone and coffee mix over the cake.
Dust your tiramisu jars with cocoa powder and place in the refrigerator for at least 30 minutes before serving.