A sandwich wafer is a thin, crisp sheet baked from a runny batter, mainly wheat flour and water, usually with a little oil, emulsifier and raising agent, between hot patterned plates. The finished wafer holds very little moisture, so it snaps cleanly and tastes of lightly toasted flour.
In ice-cream sandwiches two of these sheets enclose a block of ice cream, giving a contrast between the cold, creamy centre and the dry crunch outside, and a clean edge to hold. On Corner Chocolate Flavoured Ice Cream In Sandwich Wafer, the wafer is listed second, right after sugar, as a single ingredient.
Wafers are made from wheat flour, so they contain gluten, and depending on the recipe they may also contain milk or soy. Once they absorb moisture from the ice cream they gradually soften, which is part of the texture of this kind of bar.
