Combine coconut milk (250 ml), sugar (1 tablespoon), and cornstarch (1 tablespoon) in a pot. Heat over medium-high heat, stirring constantly, until the mixture comes to a boil (about 3-5 minutes). Add white chocolate (100 g, crumbled) and desiccated coconut (75 g). Reduce heat to low and stir occasionally for 2-3 minutes until the chocolate melts completely.
Transfer the coconut mixture to a bowl and let cool to room temperature (about 15-20 minutes). Then refrigerate for at least 1 hour until completely cold.
In a separate bowl, whip the cream (1 cup) until stiff peaks form (about 3-5 minutes).
Gently fold the whipped cream into the chilled coconut mixture using a spatula to maintain the airy texture.
Place one Raffaello candy in the bottom of each of 4 dessert glasses. Divide the coconut cream mixture equally among them, spooning the mixture on top of each candy.
Sprinkle cocoa powder lightly over each serving and place one Raffaello candy on top of each. Serve immediately or refrigerate until ready to serve.