Step 1In a large pot, combine the blackberries, 1 cup water, the sugar and lemon juice. Bring to a boil, remove from the heat and let steep, covered, for about an hour.
Step 2In a blender, puree the mixture in batches. Strain the mixture, mashing the berries against the strainer. Chill the strained soup until cold, preferably overnight.
Step 1The night before, crush the juniper berries with a spoon and add them with the cream to a small saucepan. Bring to a boil, remove from the heat, let cool until ready to refrigerate and then chill overnight.
Step 2Strain the cream, add the sugar and whip in a mixer until fluffy. Reserve, chilled, until ready for use.
Step 1Zest the 4 lemons with a zester (not a grater or microplane). The lemons should yield about one-half cup of zest, loosely packed.
Step 2Put the lemon zest, 2 cups of water and the sugar into a saucepan, bring to a boil and simmer on low heat for about 30 minutes. Remove the peel, cool on a rack or waxed paper and reserve. This can be done the day before; store the candied lemon peel in a plastic bag or container in the refrigerator.
Step 3Ladle the soup into bowls, pour one-quarter cup of club soda into each bowl, and top with a large spoonful of the juniper cream and a generous pinch of the lemon peel. Serve immediately.