This recipe combines two harbingers of spring, strawberries and rhubarb, in an unusual soup that's easy to prepare and refreshing on a hot day.
Place the strawberries, rhubarb, and orange juice in a large pan and simmer for 15 minutes or until the rhubarb is soft. Remove the pan from the heat and add the sugar, stirring until it dissolves. Taste the mixture and add more sugar if desired.
When the mixture has cooled, purée in a food processor. Pass the purée through a fine mesh sieve or chinois.
Add the strawberry liqueur, if using. Refrigerate the soup until thoroughly chilled.
To serve, ladle soup into chilled bowls and garnish each serving with a dollop of mascarpone and a sprig of mint.