Prepare the mousse:

• Soak gelatin leaves in cold water for 10 minutes.

• In a saucepan, combine frozen blueberries with a splash of water and half the sugar. Cook gently.

• Stir and mash until it becomes a thick sauce. Optionally blend for a smooth texture.

• Taste and add more sugar if needed.

• Squeeze out the gelatin and stir it into the hot coulis until fully dissolved.

• Let the coulis cool completely before continuing.

• Whip the cold heavy cream into firm peaks.

• Add a spoonful of whipped cream to the cooled coulis to lighten it.

• Gently fold the coulis into the whipped cream in three parts, being careful not to deflate it.

Assemble the charlotte:

• Use a springform pan or a 20 cm pastry ring.

• Lightly brush the ladyfingers with syrup and arrange them upright around the edges.

• Place the sponge cake or ladyfinger base at the bottom and soak it with syrup.

• Pour the mousse into the mold and smooth the top.

• Refrigerate for at least 4 hours, ideally overnight.

• Before serving, top with fresh blueberries, mint, and sliced almonds if desired.