Preheat the oven to 375F. 

Toast the pecans for 5 minutes, then set them aside. 

Add butter to a non-stick saucepan, place over a medium heat. Add the sweetener, and cook over a medium heat until the mixture is liquid and the sweetener has fully dissolved.

Continue to cook until it starts to darken and turns light brown, rather than dark yellow. Stir frequently. Add the toasted pecans and stir well.

Working quickly, divide the mixture between 24 mini muffin pan cups that have been sprayed with non-stick spray.

Leave to cool for an hour then remove them from the pan.