Harvest the herbs and rinse them under cool water; pat dry with a cotton towel. Coarsely chop the herbs, removing any stems or pieces that are damaged or brown.
Spread the herbs on a clean cookie sheet. You may want to line the cookie sheet with aluminum foil to make it easier to transfer the frozen herbs to a storage container once they are completely frozen.
Transfer frozen herbs to an airtight container or reclosable plastic bag. Frozen herbs can be kept for up to six months.
Bruise approximately 1/4 cup of fresh herbs to help release the essential oils in the herbs. You can either use one herb, or a blend of herbs like garlic, basil, and rosemary. You will know that the herbs are bruised sufficiently when you start to smell them. Place the herbs inside a glass bottle or jar with an airtight seal.
Pour oil that is at room temperature (or slightly warmed) over the bruised herbs. Seal the bottle and place it in the refrigerator. Infused oils should be kept in the refrigerator to preserve freshness.
Allow herbs to infuse into the oil for about two weeks. After that time, bring the oil to room temperature and taste it. If the flavor isn't strong enough for your taste, add more bruised herbs and infuse for an additional week.
Bring 1/2 cup (1 stick) of butter to room temperature. It should be soft and easy to work with, but not melted.
Add about 1/4 cup of finely chopped, mixed herbs to the butter. Mix until the herbs are evenly distributed throughout the butter
Place butter on a sheet of waxed paper, shaping it into a log. Chill until solid. Herbed butter can be kept in the refrigerator for up to 1 week, or frozen in an airtight container for up to three months. Alternatively, line a ramekin with waxed paper to shape the butter into a disc. The herbed butter can also be stored in a butter crock kept in the refrigerator.