Preheat an oven to 375 degrees F (190 degrees C). Grease and flour a 10 inch square cake pan.
Mix baking mix, 1/2 cup brown sugar, 3/4 cup chopped pecans, and the instant coffee granules in a large bowl.
Whisk together the egg, shortening, buttermilk, and vanilla in a separate large bowl. Stir the dry ingredients into the wet ingredients, mixing just until completely moistened.
Pour batter into prepared pan.
Mix remaining 1/4 cup brown sugar, 1/4 cup chopped pecans, and the graham cracker crumbs in a small bowl.
Sprinkle topping evenly over batter.
Bake in preheated oven until a toothpick inserted in the center comes out clean, about 20 to 25 minutes. Immediately dot top of cake with softened butter.