To cut through ganache cleanly, you can have a container of hot water handy and dip your knife into it to warm the blade. Have a clean towel to wipe most of the water from the knife. Between slicing you need to clean the blade and dip in water. Not quick, but if you work in a bakery that is how you make clean slices.
I like cutting it in squares. That's just me m
I cut the center first. Then slice it...
Thanks! Your answer is awaiting moderation.