Preheat oven to 350°. Prepare your baking sheet by lining it with parchment paper.
Using a stand mixer, cream together the vegan butter and the brown sugar. You can also use a hand mixer and a large bowl.
Beat in the vanilla extract and soy milk.
Add in the flour, unsweetened cocoa powder and the baking soda. Mix it on low speed until well combined.
Use a spoon to stir in the chocolate chips and the chopped peanuts. You can also use your hands which I think works even better. The batter will be very thick.
Roll the cookie batter into balls and place on the prepared baking sheet.
Bake for 10 minutes. Remove from oven and let the cookies rest for 3 minutes.
Optional: Use a fork to slightly flatten the cookies.
Use a spatula to move the cookies to a wire rack to cool completely.
Store the cookies in an airtight container for up to 3 days.
Notes
My favorite vegan butter is Earth Balance.
I use Trader Joe's chocolate chips which are naturally dairy-free.