In a medium microwave-safe bowl, heat 8 ounces (1 heaping cup) of the chocolate chips, the buttery spread and peanut butter on low power in the microwave oven for 60 seconds. Stir vigorously. If not melted, heat in 15 second intervals until just melted. Let cool.
In a large mixing bowl, beat the eggs, sugar, flour, vanilla, baking soda, xanthan gum and salt with an electric mixer on low speed until very well blended. Beat in tje melted chocolate mixture until no flour streaks remain. Stir in the walnuts and remaining chocolate chips. The dough will be soft. Refrigerate, covered, for 2 hours.
Preheat your oven to 375°F and line a 10x15-inch baking sheet (not nonstick) with parchment paper.
Shape the dough into 48 walnut-sized balls and place 12 balls, at least 1½ inches apart, on a sheet.
Bake just until the cookies are shiny and crust starts to crack, about 10-12 minutes. Do not over-bake.
Cool the cookies for 2 minutes on the baking sheet, then transfer to wire rack to cool completely. Repeat with the remaining dough, or freeze the dough balls up to 1 month and bake when cravings hit.
Recipe by Go Dairy Free at https://www.godairyfree.org/recipes/gluten-free-peanut-butter-dark-chocolate-cookies