Prepare the pumpkin: Peel and seed the pumpkin, cut into small pieces, and boil until tender, then mash.

Preheat the oven to 350°F (175°C) and grease a soufflé dish with butter.

Beat egg whites until stiff peaks form, about 4-6 minutes.

In another bowl, beat egg yolks until thick, then add pumpkin puree, half and half, rum, brown sugar, and spices. Mix well.

Gently fold the whipped egg whites into the pumpkin mixture.

Transfer to the greased soufflé dish and bake in a water bath for 40-45 minutes until slightly puffed.

Allow to cool slightly before serving warm, topped with whipped cream and cinnamon.