I always go with fresh juice and zest for the best citrus flavor. Bottled juice just doesn’t taste the same.
Once you add the almond flour and egg whites, mix gently. Overmixing can make the cake dense instead of light and tender.
I like to use parchment paper along with a bit of oil and flour so the cake comes out easily and doesn’t stick.
As tempting as it is to slice in early, let the cake cool in the pan. It firms up and slices cleaner once cooled.
For extra flavor and crunch, I sometimes toast the sliced almonds before adding them to the top.
To check for doneness, a toothpick inserted into the middle of the cake should come out clean.