Lemon and blueberry are such a natural match that I like to serve my posset either with a swirl of blueberry sauce in it, poured on top, or just served on the side. Simple & delicious!
The posset itself is very easy to make. Boil cream, sugar, salt, and zest together. Off the heat, add lemon juice and let sit a few minutes. Strain into a pitcher and portion into dishes or ramekins.
If swirling the sauce, thicken it with gelatin or cornstarch--I'll show you both ways in the post.Feel free to leave thickeners out and just pour the blueberry sauce on top at the table.
I think the swirl is a stunning presentation, but feel free to serve it however you choose.
If you don't like blueberries, strawberry or raspberry would be a great substitution.