Peel the pears, keep the top on, but cut a little of the bottom in order for letting in stand in an up pine position on the plate, and then use a sharp knife to gently remove the kernel.
In a pot combine elderflower juice, water, lemon juice, sugar and vanilla. Let it boil and simmer until the sugar has dissolved. Add the pears and let them simmer I the juice for 10 min.
Remove from heat and keep the pears in the pot under a lit until they are cool. Preferable let them be in the fridge overnight, this will enhance the flavor.
Serve the cold or warm pears (your choice) with a little of the juice, a dollop of crème fraiche and some fresh berries on the side.