Place the raspberries, sugar, and Meyer lemon juice in a small saucepan over medium heat. Cook gently for about 5 minutes, stirring once in a while, until the berries have softened into a saucy puree. Remove from the heat and allow to cool slightly.

Pour the heavy cream into another saucepan and warm it over medium low heat until it just begins to shimmer and show small bubbles around the edges. Stir in the champagne and keep the mixture warm for 1 minute, then take it off the heat.

Set a fine mesh sieve over the cream mixture and pour in the raspberry mixture. Press firmly with the back of a spoon or spatula to push all the berry liquid through and leave the seeds behind. Whisk the combined mixture until smooth.

Divide the posset evenly among small serving glasses or ramekins. Refrigerate uncovered for at least 2 hours, or until the cream is fully set.

When ready to serve, top each glass with a few extra fresh raspberries and a light drizzle of honey, if using. Serve well chilled.