Preheat oven to 400 degrees for a 6 cup muffin pan or 375 degrees for a dark, non-stick muffin pan.
Grease bottoms of jumbo muffin pan with vegetable shortening.
Prepare orange zest in a large bowl. Beat orange zest, milk, oil and egg with a wire whisk until well mixed. Using a large spoon, blend four, sugar, baking powder and salt and add all at once to liquid mixture, stirring just until flour is moistened. Batter will be lumpy; do not overmix.
Wash 1 cup cranberries. Put in blender on Chop (lowest setting) for 2 seconds ONLY. Fold in cranberries and nuts into muffin batter. Divide among 6 jumbo juffin cups.
Bake 20 to 25 minutes until a round toothpick pressed in the center of the muffin comes out clean. Let muffins cool about 5 minutes, then turn out onto a wire rack. Serve warm with butter.