Mint or spearmint is frequently used in Greek cuisine. Aside from the great flavor it imparts, mint is a powerful antioxidant with a variety of health benefits. We often think of mint as an herb used for sweet dishes, however it is wonderful in savory foods as well. In fact, when combining mint with tomatoes and onion, you obtain a unique flavor profile that you may not immediately connect back to mint. A non-culinary analogy I like to use, is the way the colors red and blue combine to create purple, a color we might not otherwise identify as being a mixture of the former, if it weren't for the fact that primary color combinations are one of the first things we learn in school.
Most grocers carry packets of fresh mint and it is easy to grow your own. One frustrating aspect of buying fresh mint from the store, is that you typically only need a portion of the mint in the container and by the time you are ready to use the rest, it has gone bad. As a result, I usually store the packet of fresh mint in the freezer. The same can be done with mint from the garden. You can either store it in the freezer in a zip lock bag or freeze it using water and ice cube trays.
In addition to fresh and/or frozen mint, it is always good to have some dried mint on hand. I have personally found dried mint to be scarce at grocery stores and make a point of cutting and drying some from the garden during the summer months. There are several approaches to drying mint. Once dry, you can store it in a leftover jar.