Make sure your oven rack is in the middle of the oven. Preheat oven to 350F. Line a baking sheet with parchment paper and set aside.
Use your scissors or gardening shears to cut off the leaves and put them in a salad spinner. Take the inner strainer part out, and give the leaves a good rinse. Place the strainer back into the salad spinner, and spin dry the leaves.
Lay the leaves on the parchment-lined baking sheet. For good airflow, space out the parsley leaves. If they are too crowded, the leaves might not dry all of the way.
Turn your oven down to the lowest setting (mine was at 170F). Place baking sheet with the parsley in the oven. Dry it for 20 minutes (or shorter, if your lowest temperature setting is higher than mine).
Remove the baking sheet from the oven. Check the leaves to make sure they are dry because any residual moisture is a breeding ground for mold. By dry, I mean that they shouldn't feel wet and they should crumble easily. If there are some that are still wet, set the dry leaves aside and put the wet ones back in the oven for an additional 5 minutes. Continue this cycle until all of the leaves are dry.
Once the leaves cool down, gently crush the leaves with your fingers. After crushing them, I like to put the sheet back in the oven for another 5 minutes at 170F to make sure there is no moisture left.
Fold the parchment paper into a funnel and pour the dried parsley into an air-tight storage container (I like to use glass jars). The dried parsley will retain its flavor for up to one year.