Preheat oven to 375 degrees. Grease 12 standard size muffin-pan cups or line with paper liners. Mix together flour, baking soda, cinnamon, ginger, allspice, nutmeg, and salt. Mix together eggs, apple juice, and buttermilk. Stir flour mixture and oat bran into egg mixture until dry ingredients are just moistened. Do not overmix. Gently stir in chopped apples and nuts. Spoon batter into prepared pan, filling cups two-thirds full. Garnish each muffin by placing an apple slice on top. Bake muffins until lightly golden and tops spring back when pressed, 25 minutes. Transfer pan to a wire rack to cool slightly. Turn muffins out onto rack to cool completely.

Baking Tips: Instead of frozen apple juice concentrate, use other bottled fruit juice concentrates. Health food stores generally carry the best variety. Experiment with such interesting flavors as papaya, pineapple, and mango for a tropical taste.