Coat the inside of the ramekins with softened butter. Spread an even coat all the way up to the top rim. Dust the insides of the buttered ramekins with sugar.
To prepare the soufflé base, melt the butter, and mix it with the pumpkin puree. Whisk in the egg yolks, and mix with the pastry cream until smooth.
In an electric mixer, place your egg whites with the whisk attachment on medium speed. Once the egg whites look foamy, slowly sprinkle in the sugar, and increase the speed to high. When a medium peak has been reached, turn the mixer off, and fold 1/3 of the whites into the pumpkin pastry cream base. Then add the rest of the whites to the pumpkin, and fold together until completely incorporated.
Fill the ramekins with the soufflé, leaving an inch from the top. Smooth out the soufflé so that it is flat and even.
Bake the soufflés at 350 degrees for 20 minutes.
Dust with confectioners’ sugar, or serve with a vanilla crème anglaise, or warm maple syrup. Enjoy immediately!