Someone gave me a jar (pot) of jelly made from acacia flowers, it's delicious, a very delicate flavour.
I've no acacia flowers but I have some elderberry (sureau) and I know you can make flavoured water with them.
I looked for a recipe (recette) on internet and went out just before the rain to pick (cueillir) the flowers. Here they are soaking (macérant) in 1.5 litres of hot water, as the recipe said.

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I must leave them for 3 days before filtering and making the jelly.