Prepare the baking pan by greasing it with melted butter and lining it with parchment paper.

Cut the pumpkin into bite-sized pieces and remove the skin. Microwave the pumpkin in a heatproof container covered with plastic wrap at 600W for 8 minutes until soft.

Mash the softened pumpkin in a bowl with sugar and melted butter using a masher.

Add heavy cream, milk, and beaten eggs to the mashed pumpkin mixture, mixing well after each addition. Strain the mixture through a sieve.

Sift the cake flour into the mixture and stir until fully combined and smooth.