Place the butter in a large mixing bowl and sift in one cup of the powdered erythritol.
Beat the butter and erythritol with an electric mixer on low until all of the erythritol is combined with the butter.
Add the Keto Chow and mix on medium speed until fully dissolved.
Add the vanilla extract and mix to combine.
Use a teaspoon to scoop small balls of the mixture onto a tray lined with parchment paper or wax paper.
Chill the bon bons in the refrigerator or freezer until they are firm.
Sift the remaining powdered sugar together with the instant coffee powder, if using.
Roll the chilled bon bons in the erythritol, shaking off the excess before returning them to the lined tray.
Store the bon bons in an airtight container with parchment paper between layers. Store in the refrigerator or freezer for up to three months.