Feel free to mix and match whatever kind of berries you'd like. Blackberries, cherries, red currants can all be part of the mix, or feel free to go "classic" and use all strawberries. You're also welcome to tweak the sugar amount used to sweeten the berries, which can vary depending on how naturally sweet they are. The
kirsch is optional; a little improves the flavor of the berries. But if you don't want to use it, a splash of crème de cassis or lemon juice can also heighten their flavor.
You'll likely get a few extra biscuits from the dough if you reroll the scraps. They can be enjoyed for breakfast the next morning, with some butter and jam, or they frozen for up to two months and used to make more shortcakes in the future.