I don't understand the 12/3 cups of sugar or the 11/3 cups of flour and see nothing about that in the comments

Idiosyncrasies with the Food52 page layout design and how the pages interact with various web browser software make some recipes rather inscrutable.

I see you registered today. Expect to see similar head-scratching instructions on other recipe pages on this website from time to time. Use your best judgment and common sense to determine the actual intent of the recipe author.

Of course, if you have a question about a recipe, your best bet is to contact the recipe author directly. That also serves as an alert to that author that there is possibly a problem with the recipe in *ALL* of the places that it is posted (many recipes posted here are cross-posted on multiple websites).

Yes, as cremated said, it is 1 cup plus 2/3 and 1 cup plus 1/3. There is a space between the 1 and the fraction in the recipe, but it's small.

It probably means 1-2/3 cups sugar and 1-1/3 cup flour.