How to Make It
In a saucepan, combine the rhubarb with the sugar, water and salt and bring to a boil. Simmer over moderately low heat, stirring occasionally, until the fruit is very soft, 20 minutes. Strain the syrup through a cheesecloth-lined sieve into a heatproof bowl, pressing. Stir in the lemon juice. Let the syrup cool, then refrigerate until chilled, about 45 minutes.
In a large bowl, beat the cream with the maple syrup until firm peaks form. Put the blueberries in bowls or glasses and top with the maple whipped cream. Spoon some of the rhubarb syrup on top and serve.