The ratio for this recipe is 1/2 cup of kosher salt to 1 cup of herbs. All but the rosemary can include the stems. For rosemary, strip the leaves off the stems and use only the leaves.
In a food processor, add the herbs and salt. Pulse the mixture until it is a thoroughly combined and the herbs are broken down.
Spread the mixture on a rimmed baking sheet lined with parchment.
Let the mixture air dry at least overnight undisturbed in a cool, dry location. Alternately, you could place the sheet in a 150-degree (or very low) oven for 1-2 hours, checking and stirring frequently so as to avoid any singeing or burning of the herbs.
Store the completely dried herbed salt in a glass container for up to 6 months unrefridgerated.