Dissolve yeast in 1/4 cup of the water; let stand 5 minutes until frothy. Put flours and salt into a large bowl; make a well in the center. Add yeast mixture, remaining water and oil and mix to a soft dough.
Knead on a lightly floured surface about 5 minutes or until smooth and elastic. Put into a clean bowl, cover with a damp cloth and let rise in a warm place 1-1/2 to 2 hours or until doubled in size.
Preheat oven to 425 degrees F. (220 degrees C.).
Punch down dough. Knead dough 2 minutes, then roll into a 12-inch square. Spread with mustard, then sprinkle with cheese and parsley.
Roll up like a jellyroll and place, seam side down, on a floured baking sheet; brush with water and sprinkle with mustard seeds.
Bake 10 minutes; reduce temperature to 400 degrees F. (205 degrees C.) and bake 20 minutes or until bread sounds hollow when tapped underneath. Cool on a wire rack.
Variation: Use 1 cup light beer instead of 1 cup of the water.