Other than the icecream stop (http://eatlikeushi.posthaven.com/efstidalur-ii-iceland-01-2018), a lunch stop was planned at either the tomato farm at Fridheimar or Fontana. I was hoping that with the geothermal bread they are famous for, there would be sandwiches and other options for takeaway to keep on the move and maximise the use of daylight.
They have a buffet lunch (and dinner) available for 2990ISK or 3990ISK but unfortunately the only sandwiches were thin bread open with smoked salmon and nothing else (for about 2000ISK). We didn't have time for buffet and the price for once little open sandwich seemed difficult to justify and so it was fortunate they sell the bread by itself in quarter loaves at 1250ISK each.
We ended up buying smoked salmon from Bonus and some nice cheddar cheese which filled out a couple of days of lunches. The rye bread is surprisingly sweet and no wonder it requires alternative flavours to balance it (ie. smokey fish).
I wouldn't pay that price for it but I'd be happy to eat it again.