Preheat the oven to 410°F (210°C). In a large mixing bowl, cream together the cold butter, brown sugar, and granulated sugar, and mix for at least 4 minutes, or until the mixture is light and creamy.

Add the eggs and vanilla extract, and continue mixing for an additional minute.

Next, fold in the cocoa powder, cake flour, all-purpose flour, cornstarch, baking soda, and salt until combined. Stir in the semi-sweet chocolate chips, mini marshmallows, and chopped cashews.

Roll the dough into large balls, about 5 to 6 ounces each, and place them on a parchment paper-lined baking sheet. It’s recommended to use a light-colored baking sheet for even baking.

For a more gourmet look, top each cookie with a few extra chocolate chips and marshmallows, gently pressing them into the dough.

Bake the cookies for 9-11 minutes. After removing them from the oven, if the marshmallows are melting too much around the edges, use a small brownie spatula to gently push the edges towards the center while they cool. This helps to shape the cookies into a perfect rocky road form.

Allow the cookies to rest for 15 minutes on the baking sheet to set before removing them.