In a large bowl, beat the heavy cream until stiff peaks form. Set aside.
In another bowl, mix mascarpone cheese, sugar, and vanilla extract until smooth and creamy.
Gently fold the whipped cream into the mascarpone mixture until well combined.
In a shallow bowl, combine espresso and coffee liqueur (if using).
Quickly dip each piece of ladyfinger into the coffee mixture (do not soak).
Layer dipped ladyfingers at the bottom of small dessert cups or jars.
Spoon or pipe a layer of the mascarpone cream on top.
Repeat layers once more, ending with a final layer of cream.
Chill the tiramisu cups in the fridge for at least 2 hours, or overnight for best results.
Before serving, dust with cocoa powder and top with chocolate shavings if desired.