Stir bran and margarine into boiling water; set aside until cooled to very warm (120º to 130ºF).

In large bowl, combine 5 cups flour, undissolved yeast, brown sugar and salt. Stir in bran mixture, dates and enough additional flour to make a soft dough. Knead on lightly floured surface until smooth and elastic, about 8 to 10 minutes. Cover; let rest 10 minutes.

Divide dough into 2 equal portions. Form into 6-inch diameter balls. Place on greased baking sheets. Flatten slightly with hand. Cover; let rise in warm, draft-free place until doubled in size, about 45 minutes. With sharp knife, make eight 1/4-inch slashes in crisscross fashion on top of loaves.

Bake at 400ºF for 30 minutes, or until done. Remove from baking sheets and cool on wire racks.