1Puree berries & orange juice in blender or food processor. Strain mixture into 4-qt. stainless or glass saucepan. Combine tapioca with 1/4 cup of mixture; Add back to saucepan, along with spices. Heat to boiling, stirring constantly, cook 1 minute.
2Add sugar, lemon peel, lemon juice and buttermilk. Using a hand blender/electric whisk, blend until smooth. Chill for at least 2 hours in refrigerator.
3Preheat oven to 325°F. Cut pound cake into 1/2" cubes and place in single layer on baking sheet. Bake for 6-10 minutes, or until lightly browned.
4Divide soup into four bowls and top with a few croutons. Can also garnish with thin lemon slice or strawberries.