I used yellow summer squash here because I liked how the visible squash strands suggested lemon while the visible basil strands suggested the more-familiar-in-a-loaf-cake zucchini. But you could certainly use zucchini as an equal substitute. A few tips:
1.Grate the squash into a colander right after you preheat the oven. That will allow some of the moisture to drain.
2.I realize cake flour seems fussy, and I did test this with all-purpose flour to see if you could use that. But the cake flour yields a superior texture (I think the acid in the lemon makes it necessary), and it’s easily available. I used the White Lily brand. You can sub AP flour if you take out 1 tablespoon per cup and replace it with cornstarch (so this recipe would be 2 cups – 2 tablespoons AP flour + 2 tablespoons cornstarch).