1. Prepare the Crust:

1. Make blueberry puree: In a small saucepan, combine blueberries, 1/4 cup sugar, lemon juice, and zest. Cook over medium heat until berries burst and mixture thickens (about 8 minutes). Blend until smooth, then strain through a fine mesh sieve. Let cool.
2. Bloom gelatin: Sprinkle gelatin over cold water in a small bowl. Let stand 5 minutes. Gently warm over low heat until dissolved. Stir into cooled blueberry puree.
3. Make blueberry mousse: In a large bowl, beat cream cheese, remaining 1/4 cup sugar, powdered sugar, and vanilla until smooth. In another bowl, whip heavy cream to stiff peaks. Fold cream cheese mixture into whipped cream, then fold in blueberry gelatin mixture. Divide among 8 silicone dome molds (about 1/2 cup each). Chill 10 minutes.
4. Fill centers: Spoon a small indentation into each mousse dome. Fill each with 1 tablespoon lemon curd. Cover with a thin layer of remaining mousse to seal. Freeze at least 4 hours or overnight.
5. Prepare crystal glaze: In a small saucepan, combine water, sugar, corn syrup, and lemon juice. Bring to a boil. Remove from heat and whisk in agar-agar until dissolved. Pour into a shallow dish and let cool to room temperature (it will set into a thin, clear gel). Gently rewarm just until liquid (do not overheat).
6. Assemble and glaze: Unmold frozen domes onto a wire rack set over a tray for drips. Working quickly, spoon or pour the crystal glaze over each dome, allowing excess to drip off. Let set at room temperature for 5 minutes. Optionally, garnish with edible gold leaf or shimmer dust. Serve immediately or refrigerate up to 2 hours.