In a bowl mix the cream cheese with the onion and garlic powders. Shape into a disk, wrap in plastic wrap and refrigerate for 1 hour or up to a couple days ahead.
Before serving, unwrap the cheese and place on a platter.
In a medium skillet over medium heat, toast the pecans until fragrant, about 4 minutes. Add the butter and let melt. Lower the heat to medium-low, add the Swerve, Worcestershire sauce, salt, mustard, and cayenne pepper. Heat, stirring frequently, until the Swerve is completely melted and everything is well incorporated. Let cool a few minutes then spoon the mixture over the cheese. Serve with crackers.