A date becomes orderable on the A la carte page when all of the following are true for the customer's kitchen:

1. The delivery date exists and is open (not closed by cut-off or manually, and not finished) - it shows green in the menu calendar.
2. The date falls on a Meal Prep fulfilment weekday of the kitchen location (and, if a delivery method/route limits weekdays, on one of those days).
3. The date has at least one meal on the Meal Prep Menu - build it with Select Meals For this day, Select A Preset Menu, Randomly Generate a Menu, or Clone; otherwise it is grey "No Menu".
4. The date is later than the cut-off (Allow Orders on Past Open Dates decides whether today's/past open dates count).
5. The date is within the number of upcoming dates allowed by Theme: Kitchen > Calendar Visible Date Range.

Once those hold, customers see the date in the date picker and the menu meals load. Menu changes are live immediately; there is no publish button.