Tip out the syrup leaving 3 tbsp behind in the pan, add the rhubarb and heat it slowly in the syrup. Make sure the syrup doesn’t burn as the rhubarb softens, and when it is completely soft, leave it to cool. If the rhubarb is still tart, add a little more syrup. Whip the cream to soft peaks, break in the meringues and add most of the rhubarb. Fold everything together. Divide the mixture between bowls or glasses, and add more rhubarb and a sprinkle of rosemary to each. Add the leftover rosemary to a jar of sugar and seal to make rosemary sugar.