Place all ingredients for the magnums in your blender or food processor (only 1 cup of cherries) and blend on a high speed until smooth and lump free.
Pour the mixture evenly into your moulds. Transfer to the freezer and freeze for 8 hours or overnight.
After frozen, melt the chocolate and add the peanut butter. Transfer the melted chocolate into a tall glass, easy for dipping. Thinly slice the remaining frozen cherries.
Remove one magnum from the freezer at a time and dip to coat. Allow any excess to drip. Press one cherry slice on top. The chocolate should harden within several seconds. Transfer the magnum back to the freezer on a plate with baking paper, then repeat the same process with each magnum.
