I decreased the butter and added more juice as I wanted the icing to be mostly grapefruit, not butter. I also added some extra zest to pump up the flavor. I refrigerated my icing for a day along with the dough. Then I popped the icing in the microwave for 15 seconds until it was spreadable like lemon curd. Worked for me. Hopefully these modifications help with any other icing troubles out there.

The filling / frosting is indeed runny. I ended up making a royal frosting using grapefruit juice insted of lemon juice. They were good

The filling / frosting is indeed runny. I ended up making a royal frosting using grapefruit juice insted of lemon juice. They were good

The cookies were easy enough to make but my frosting didn't set up right for sandwich cookies, I had a big squish mess! Fishnlady's suggestion was a good one. I probably won't make these again.

thanks fishnlady! I was curious about an alternative and will try your version

Has anybody made this filling yet? Is the taste of the honey very prominent?

I find frosting made this way is too squishy for a sandwich type cookie. It would be better to use grapefruit juice and powdered sugar with a tiny amount of butter. Like 2 cups powdered sugar, juice to consistency and 1 teaspoon butter. Makes a great tasting frosting.