Crush the peppermint leaves with your hands or a spoon.
Add the crushed leaves into a glass jar and pack them in there until the jar is full.
Fill the jar with olive oil covering all the leaves, till the neck level.
Let the oil steep in now. If you live in a warm place let the oil steep in for 2 days in the sun and shake the glass jar every 12 hours. If it is winter where you live, place the jar in your cabinet and let it steep in for 1 month.
After the steeping period is finished, strain the oil using a double folded cheesecloth or using a fine strainer.
Store the peppermint oil in a dark, dry and warm place. It will stay for 3-6 months.
Avocado oil is a great substitute for olive oil in this recipe.