Stir with ice, strain, coupe, garnish with cherry
Reversing the proportions of the sherry and punsch makes a slightly richer, if sweeter, drink. At least with my home-made punsch, which errs a little on the sweet side.
We weren't greatly enjoying our sloe gin. This was an attempt to tame its dominant flavour; it was successful enough we may now need to replace the bottle. I started with dry vermouth instead of sherry, but the drink was far too sweet. The idea of dry sherry was one of those middle-of-the-night revelations.