Prepare gelatin by sprinkling it into water in a bowl and let it bloom. Divide sugar into 50g and 20g portions.

Place frozen pumpkin in a microwave-safe container, cover loosely with plastic wrap, and microwave at 600W for about 5 minutes until soft. Remove skin and blend in a food processor with egg yolk and vanilla essence until smooth (pumpkin paste).

Heat milk and 50g sugar in a saucepan over medium heat, stirring until sugar dissolves. Remove from heat, add bloomed gelatin, and stir until dissolved. Let cool slightly.

Place the saucepan over an ice bath and stir until thickened. Add pumpkin paste and mix well with a whisk.

Whip 100cc cream with 20g sugar using a hand mixer until it reaches a ribbon-like consistency. Strain the mixture from step 4 into the whipped cream and mix (mousse mixture).

Divide the mousse mixture evenly into serving dishes and refrigerate for about 2 hours until set (pumpkin mousse).