Wash and pit all of the cherries. I highly recommend a cherry pitter to make this process cleaner and faster.
In a large bowl, mix the pitted cherries with the Grand Marnier, sugar and zest. Cover and let them macerate in the refrigerator for at least 3 hours, stirring occasionally. I recommend letting them sit overnight.
Prepare the filling:
In a stand mixer, whisk the cream, mascarpone, sugar and vanilla until they reach a stiff peak. Be careful not to over-whip. Set aside.
Prepare the simple syrup:
Bring water and sugar to a boil.
Let the mixture cook until the sugar has completely dissolved. For a thicker syrup, allow the mixture to reduce for several minutes.
Allow to cool.
Assembly:
Once the first three components are prepared, bake the biscuits.
Allow them to cool slightly, then cut in half.
Pipe or spoon a generous amount of the filling onto the biscuit, then top with drunken cherries. Drizzle some of the cherry juice on top.
Pipe a bit more filling on top of the cherries, then top with the second half of the biscuit.
Pipe some filling on top and garnish with a cherry.
Drizzle simple syrup on top of or around the shortcake.
Notes
You may have leftover drunken cherries, depending on how much you use with each serving. I recommend enjoying them over vanilla ice cream :)