Wash and dry the pumpkin. Then cut a piece, remove the fibers and seeds. Peel the skin (lay the piece on a cutting board and peel downwards) and grate on a fine grater.
In a bowl, mix the flour, baking powder, a pinch of cinnamon, and salt. Mix thoroughly.
In a tall container, such as a blender jug, place the egg and sweetener. Beat with a mixer or hand whisk for several minutes until fluffy and the sweetener dissolves. Gradually add the oil while continuing to mix.
Add the pumpkin to the egg mixture and gently, but thoroughly, mix with a spoon.
Then combine the pumpkin-egg mixture with the dry ingredients. Stir and rub with a spoon until the ingredients are combined and the mixture is uniform (without flour lumps).
Transfer the mixture to a small baking pan lined with parchment paper. Bake in a preheated oven at 180°C until lightly risen and golden brown, about 30-40 minutes. Leave the cake to cool in the pan.
Remove from the mold and cut only after it has completely cooled.