To freeze for sandwiches and Stroganoff:
Slice half of brisket across grain into thin slices, for sandwiches. Cut other half into 3/4-inch chunks, for Stroganoff. Let gravy cool slightly. Combine sliced meat with 1 cup gravy in freezer container or heavy-duty freezer bag. Combine beef chunks with remaining gravy in second freezer container or freezer bag. Seal and label. Refrigerate until completely cooled. Freeze.