Preheat oven at 180 degree C. Grease donut tray with butter.
Sift together flour, salt, and baking powder in a bowl. Set aside.
Whisk together butter and sugar using hand blender until light and fluffy. This might take 5 minutes depending upon the speed of the blender.
Add one egg at a time and whisk the batter for 2 minutes each time.
Now add the vanilla and combine the batter using spatula.
Add the flour mixture in small batches and mix gently using a spatula.
Once the batter is nicely combined stop mixing.
Fill the greased doughnut tray with the batter. Fill each cavity upto 2/3.
Bake for 20 to 25 minutes, or until doughnuts are nicely baked. Allow them to cool.
Heat cream in a pan and add one tablespoon of butter. Mix nicely.
Pour this warm liquid over the Nutella and whisk to form a smooth glaze.
Dip each doughnut in the Nutella Glaze and serve.