Preheat oven to 200 degrees. Line baking sheet with parchment paper.
Arrange celery leaves in single layer on prepared baking sheet. Bake 20 minutes, rotating pan halfway through baking time.
Remove from oven and cool slightly. Transfer to spice grinder. Add salt and process until finely ground. Cool completely and store covered in pantry.
Notes
Celery leaves: Store-bought celery salt is made from ground celery seeds and salt. In this version, we reduce food waste by drying out and grinding leftover celery leaves.
Yield: The amount of leaves per bunch of celery varies, but I was able to get it about 1 cup of loosely-packed celery leaves from one bunch celery. That yields about 2 tablespoons celery salt.
Storage: Store the celery salt in an airtight container in a dark place for up to 6 months.
Freezer: Store Homemade Celery Salt in the freezer indefinitely.