The ornamental design for a baking pan with a removable insert, as shown and described.
FIG. 1 is a top, front and right perspective view of the baking pan with a removable insert showing my new design;
FIG. 2 is a top plan view thereof;
FIG. 3 is a bottom plan view thereof;
FIG. 4 is a front elevational view thereof; the rear elevational view, the right elevational view and the left elevational view being a mirror image; and,
FIG. 5 is an exploded perspective view thereof, shown with the inserts removed for completeness of illustration.