In a medium saucepan, combine the water, unsalted butter, and granulated sugar. Bring the mixture to a gentle boil over medium heat, stirring occasionally until the butter is fully melted.
Remove the saucepan from heat and immediately add the all-purpose flour and salt. Stir vigorously with a spatula until the mixture comes together to form a smooth ball of dough that pulls away from the sides of the pan. Allow it to cool slightly for about 5 minutes.
Once the dough has cooled, add the eggs one at a time, mixing thoroughly after each addition until fully incorporated. The dough should be smooth, silky, and glossy.
Next, stir in the vanilla extract until well blended and uniform in texture.
In a deep frying pan, heat approximately 2 inches of vegetable oil over medium-high heat until it reaches a temperature of 350°F (175°C).
When the oil is hot, use a small ice cream scoop or two teaspoons to carefully drop rounded balls of dough into the hot oil, taking care not to overcrowd the pan. Fry in batches if necessary.
Fry the beignets for about 3-4 minutes on each side, or until they are golden brown and puffed up. Use a slotted spoon to remove the beignets and transfer them to a plate lined with paper towels to absorb any excess oil.
While the beignets cool slightly, whip the heavy cream and powdered sugar in a mixing bowl using an electric mixer until soft peaks form, creating a fluffy whipped cream.
Once the beignets are just warm to the touch, use a toothpick or skewer to make a small hole in the side of each. Gently pipe the hazelnut spread into the cavity, followed by the whipped cream until filled.
To finish, dust the beignets generously with extra powdered sugar for a delightful presentation before serving.
Notes
Serve on a decorative platter with extra powdered sugar and hazelnut spread for dipping.