Which side of the bread do we butter evenly, from edge to edge?

The correct answer is the convex side of the bread. When preparing sandwiches or other items where buttering is essential, it is important to evenly coat the convex side, which is the outward-facing, rounded side of the slice. This ensures a well-distributed layer of butter that enhances flavor and helps achieve the desired texture when grilled or toasted.

Using the convex side allows for optimal coverage, ensuring that the butter melts uniformly and contributes to an appealing golden-brown crust during cooking. Properly buttering this side also prevents sticking to the cooking surface, making flipping and handling easier. The other sides of the bread, such as the concave or rough sides, are not typically buttered in this manner for preparing sandwiches, as they do not provide the same advantages in terms of flavor enhancement and texture when cooked.