Pour 60 ml of the cold water into a small bowl. Sprinkle the powdered gelatin evenly over the surface and let it sit for 5 minutes until the gelatin swells and looks spongy.

Pour the remaining 320 ml of cold water into a small saucepan. Add the caster sugar and set over medium heat. Stir gently until the sugar dissolves, about 2 minutes. Do not boil.

Remove the pan from the heat. Add the bloomed gelatin and stir gently until it fully dissolves, about 1 minute. The mixture should be completely clear with no visible gelatin granules.

Stir in the violet syrup and lemon juice. Taste and adjust sweetness if needed.

Strain the mixture through a fine-mesh sieve into a measuring jug.

Divide the jelly mixture evenly between 4 serving glasses. Let the mixture cool to room temperature, about 10 minutes.

Cover each glass with plastic wrap and transfer to the fridge. Refrigerate for at least 4 hours, or overnight, until firmly set and clear.

When ready to serve, whip the cold heavy cream to soft peaks using a hand whisk or electric mixer.

Remove the glasses from the fridge, uncover, and add a generous spoon of whipped cream to each. Top with candied violet flowers if using and serve immediately.