The phrase "sandwich loaf" refers to a type of food that is made by layering different ingredients between slices of bread. It is like a big sandwich that can be sliced into smaller pieces for people to eat. Full definition
Never dump those extra starter... always use them in making sandwich loaf with a little bit of yeast.. (delightfulrepast.com)
The recipe below will give you a chance to take a trial run at the recipe and see if you want to give the full, sandwich loaf version a go. (glutenfreecookingschool.com)
It made a beautiful lighter sandwich loaf, and I would highly recommend it for that. (kingarthurflour.com)