1 Squeeze out the lemon juice and measure 1 tablespoon juice. Cut cress from the roots.
2 Rinse radishes, wipe dry and coarsely chop.
3 Combine lemon juice, radishes, buttermilk, paprika and salt in a blender and puree until smooth. Add sweetener to taste. Pour into an ice-filled serving glass, garnish with cress and serve immediately.