The ornamental design for a two-slice toaster, as shown and described.
FIG. 1 is a top front right perspective view of the two-slice toaster showing the new design;
FIG. 2 is a left side elevation view thereof and being the same as the right side elevational view thereof;
FIG. 3 is a front elevation view thereof;
FIG. 4 is a top plan view thereof;
FIG. 5 is a rear elevation view thereof; and,
FIG. 6 is a bottom plan view thereof.