Purchase the best pipe tobacco you can and infuse it sparingly with mint extract, either on a sponge inside a baggie, or by misting the tobacco very lightly. OR pop a mint tea bag into your tobacco jar and let it develop flavor over a few days.
I would not try to use essential oil in any manner. It may be ok but it’s not foolproof.
Oh dang, This was supposed to be in the menthol cigarette thread. I’m sorry.