I always chill my orange juice, cranberry juice, and club soda in the fridge for a few hours before mixing. Cold ingredients mean I don't need as much ice, which keeps the punch from getting diluted. If you're short on time, a quick spin in the freezer for 20 minutes works too.
In a large pitcher, I combine the spiced rum, orange juice, and cranberry juice together. I stir it well so the flavors blend evenly instead of settling at the bottom. This base can sit covered in the fridge for a few hours before your party starts.
Right before I'm ready to serve, I pour the chilled base into my punch bowl or cauldron. Then I top it with the club soda so it stays bubbly instead of going flat too early. I give it one gentle stir, just enough to combine without losing the fizz.
I pour the punch into my plastic cauldron or punch bowl and add a big block of ice to keep it cold. If I'm using frozen cranberries or blackberries, I drop them in now so they float around like little potion bits. This step is really what makes the drink feel like a Halloween showpiece.
Finally, I garnish the top with a few lemon wedges and let guests ladle their own glass. I keep extra lemon wedges nearby in case anyone wants a brighter, more citrusy pour. Serve it right away while it's still cold and fizzy.