Preheat oven to 400 degrees. Grease bottoms only of a standard-sized 12 muffin cup tin. Beat together oil, yogurt, brown sugar and eggs. In a separate bowl whisk together the whole wheat flour, all-purpose flour, cornmeal, baking powder, baking soda and salt. Add flour mixture to the wet ingredients and mix until moistened. Fold in cranberries and walnuts. Divide batter evenly among the muffin cups - they will be very full. Bake 20-22 minutes or until golden brown. Remove immediately from pan.
Notes
Check muffins after 19 minutes. These muffins are on the dry side. They are excellent the next day. Using dried cranberries will increase the sweetness.