Since Elizabethan times tansy has been associated with rhubarb dishes.

1 pound rhubarb, trimmed and cut into 1 in lengths
Pinch of ground ginger
1/2 cup water
2 eggs, separated
2 tsp chopped tansy
Juice and zest of 1 lemon
Scant 1/3 cup sugar
2/3 cup heavy cream

1- Put the rhubarb in a large bowl with the ginger and water. Cover and cook on HIGH for 10-12 minutes, stirring twice, until the rhubarb is mushy.

2- Stir in the egg yolks, tansy, lemon juice and zest. Purée in a food processor or blender.

3- Whisk the egg whites to form soft peaks, then whisk in the sugar, half at a time.

4- Whip the cream to form soft peaks and fold into the rhubarb mixture. Fold in the egg whites and spoon the mixture into glasses. Chill thoroughly before serving with crisp cookies.