Add the butter to an electric mixer and beat for 1 to 2 minutes until the butter is soft. Add ½ cup of the powdered sugar to the butter until it is creamy and light.
Add the vanilla to the butter and sugar mixture and mix it in with a spoon.
In a separate bowl, whisk together NESTUM®, almond flour and salt.
Mix the dry ingredients into the butter mixture. The dough should hold together when squeezed between your fingers.
Cover the dough and let it rest in the refrigerator for at least 30 minutes.
Heat the oven to 400°F (~200°C).
Roll the dough into 1 ½-inch balls and place them about 1 inch apart on an ungreased cookie sheet.
Bake the cookies for 10 to 12 minutes or until they are golden brown.
Remove the cookies from the baking sheet and let them cool on a wire rack for about 5 minutes.
Place the remaining powdered sugar in a bowl. Roll the warm cookies in the powdered sugar. Let the cookies cool completely, and then roll them in the powdered sugar again to give them a generous coat.