The ornamental design for a reversible baking tin, as shown and described.
FIG. 1 is a side, top, perspective view of the reversible baking tin;
FIG. 2 is a top view thereof;
FIG. 3 is a front side view thereof, the rear side view being a mirror image of the front side view;
FIG. 4 is a left side view thereof, the right side view being a mirror image of the left side view;
FIG. 5 is a side, bottom, perspective view thereof; and,
FIG. 6 is a bottom view thereof.
The broken line showing of muffin cups in FIGS. 1 and 2 are for illustrative purposes only and form no part of the claimed design.