In a mixing bowl, combine softened unsalted butter, powdered sugar, and vanilla extract using a mixer until creamy and smooth.

Add a pinch of salt for flavor enhancement and gradually incorporate milk until you achieve a silky consistency.

Take a fresh wafer sheet and spread an even layer of the creamy filling across the surface, leaving a small border.

Sprinkle a generous amount of raisins over the filling before rolling the wafer tightly from one end to the other.

For a firmer texture, refrigerate the rolled wafer for about 15 minutes.

After chilling, slice the roll into bite-sized pieces, aiming for about 1 to 1.5 inches in thickness.

Arrange slices on a serving platter and dust with powdered sugar if desired.