Can You Upgrade Food Items?

Hi guys, trying to put together a restaurant website -- I can't seem to see any functionality to be able to charge additional "upcharge" for adding on an item to your product.

For instance. You select a 2 piece fried chicken product with fries. I can list other options from fries that would cost the same, but perhaps I want to charge more for onion rings, there is no functionality to do that, so I cannot add "up-sell's or upcharges" to the site? Is this correct, is there a workaround? Any help would be great. Thanks!

Is there any actual support from Squarespace that isn't paid? I mean it's a simple question on functionality. Really regretting my purchase now and thinking of just scrapping the $70 I paid to move to Wix... Can anyone advise please?

This is a Squarespace community forum but you can contact Squarespace Customer Care directly for free support using this link. 

In the meantime, you may find the following support articles helpful:

Adding basic product variants

Displaying related products

Does anyone have any updates for this? I'm looking to be able to do a Build Your Own Juice, and need the same functionality. Thanks!