Currently, it is not possible to export a Menu or Menu Items. There are two ways however to get this information.
When viewing your Menu Items, you do have the ability to highlight + copy them. From there, it's possible to paste & further manipulate them in Excel:
You can create a fake Booking with one of each Menu Item you would like to export. You are then able to pull a Report as a CSV with this information. This can be done by following these steps.
Create a fake Booking (name it something obvious, no need to set a date)
Click on the Line Items Tab within the Booking Details Page
Click +Add Multiple Items
Add one of each Item you want to export
Go to Reports
Open Line Item List (Booking)
Add a filter for 'Booking,' choosing the fake Booking you created earlier.
Arrange the columns to choose the information you would like to export
Choose Export As CSV
Be sure to Delete or Archive the Booking afterwards so it doesn't affect your reports