In a small saucepan, melt butter over medium-high heat (heat until it turns brown, not black).
Add natural sweeteners until sweeteners dissolve and the mixture bubbles just a little.
Using a hand mixer on low speed, add in extract and mascarpone/cream cheese.
Mix until combined.
The mixture will not emulsify until it cools a little. NOTE: I placed the mixture into my blender and combined until smooth which caused it to not separate. If you use a hand mixer, it keeps separating until cooled. So after it cools a bit, whip it together.
Stir in the nuts and ginger if using.
Place a piece of parchment in an 8 x 8 square baking pan. Pour mixture into the pan lined with parchment. Refrigerate overnight, the mixture will thicken a lot. Remove from pan, peel away parchment and cut into 1 inch cubes.