Heat milk over low heat until just below boiling. Remove from heat;stir in butter, honey and salt. Set aside and let cool.
In a large bowl, combine yeast and lukewarm water. Set aside 5 minutes for yeast to soften. Add cooled milk mixture to softened yeast and beat in 4 cups flour.
Knead dough in a bowl, adding up to 1/2 cup more flour if necessary, until a smooth, soft dough forms. Divide dough into 8 balls 3 inches in diameter. Place balls 4 inches apart on lightly greased cookie sheets; pat into 4 inch rounds. Set aside, lightly covered with kitchen towels, about 1 hour, or until doubled in size.
Preheat oven to 350 degrees F (180 degrees C).
Bake raised rounds 30 minutes, or until golden brown. Remove from oven; leave oven on. Let cool on sheets 10-15 minutes, or until cool enough to handle.
With a serrated knife, cut each round into six 1/2-inch slices. Place slices, cut sides down, on cookie sheets and return to oven 5 minutes. Turn slices and bake 5 to 7 min. longer, or until golden on both sides. Turn off heat and leave zwieback in unopened oven until cool, about 45 minutes. Store in a tightly covered container.