In large mixing bowl, activate the yeast in the warm water. Allow to set until bubbles form. Add the kefir, sugar, salt, olive spread, zest and fennel seed. Mix well. Stir in the bread flour, then add white whole wheat to make a soft but firm dough. It may take less than the full amount. Knead, by hand or mixer, for 5 minutes until sot and smooth. Place in a lightly greased bowl, cover and set aside in a warm place to rise, for 1-1/2 hours.