Preheat oven to 375°F. Line cookie sheet with parchment paper and set aside.
Whisk together flour, cocoa, baking soda and salt. Set aside.
1 ½ cups all purpose flour, ½ cup unsweetened baking cocoa, ½ teaspoon baking soda, ½ teaspoon fine sea salt
Cream sugars, butter and peanut butter together until light and fluffy.
¾ cup light brown sugar, ½ cup granulated sugar, ¼ cup unsalted butter, ¼ cup creamy peanut butter
Add in egg, vanilla and coffee and beat until well blended.
1 large egg, 1 teaspoon vanilla extract, 2 tablespoons coffee
Gradually stir in dry ingredients. Fold in chopped pecans.
¾ cup chopped pecans
Scoop out rounded tablespoons of cookie dough onto prepared cookie sheet. Dough is very thick.
Flatten each cookie slightly and bake for 6 minutes. Remove from the oven.
Lightly press half a marshmallow, cut side down, into the top of each cookie. Bake for another 1 to 2 minutes.
12 large marshmallows
Remove from oven, let cool for a few minutes before transferring to a cooling rack to cool completely.