It's been awhile since I've posted here; my life has been on fast-forward. That said, I'm still interested in oregano liqueur and have found the following recipe to be delicious:
2 Tequila
1 Lime Juice
1 Oregano Liqueur
1 Banana Liqueur
To make the oregano liqueur, steap one jar of oregano in 400g of 95% grain alcohol for 2 weeks. Then strain and add 1000g of 2-water-to-1-sugar syrup. Adjust syrup to taste.
This cocktail is fire. I think it's good enough to warrant making the liqueur. That said, there are other flavors that pair well with oregano: mango, blackberry, raspberry, and triple sec. I find rhum agricole or cachaca also pairs well with oregano.