I Received a gift of strop shop peppermint about a year ago and I have to say it's a very fine though strident scent. It lathers well and easily so I was hesitant to pitch it. I thought it might grow on me and honestly never really did. I finished a few pucks and recently purchased a puck of amici which is very intriguing in its own right. Anyway I decided to have a go at moding the peppermint puck. I used a toothpick and punched a couple dozen holes in the puck and added 20 drops of orange and 10 drops of lemon essential oil. I gently stirred it with a toothpick, pressed it all smooth and then let it sit. After a week I tried it and it wasn't there scent wise so I perforated it again and hit it with 20 more drops of orange and let it sit. Another week it was closer so 10 more drops of orange and 10 of geranium and let it sit. Well after another week it is a great orange peppermint shave so I am going to call it good for now. It's certainly livened up the soap. Later on I might add some spice like allspice or clove to balance the scent. The experiment was a success and I thought I would share my experience should you have a puck that works splendidly but doesn't have quite the scent you like.
I believe the EO could also be added to the lather as well, which may make it easier to get the right ratio you are looking for. It is fun to experiment and tweak the scent, which also could be done by superlather (mixing 2 soaps, or creams, and maybe a few drops of glycerin). Making homemade menthol glycerin and adding it to whatever lather you wish is a great way to mentholate any product.
That sounds interesting, might try something on that same line with some of the pucks I have from several different soaps.
I have some of Em's Woodstock EO. Two drops in my lather bowl is plenty to smell up the vintage Colgate Barber's soap I have.