Preheat oven to 350°F. Spray a 9X9 inch pan with baking non-stick spray. Line the bottom and 2 sides with a parchment paper and spray again.
In a mixing bowl, sift the flour, cocoa powder, baking soda, and salt. Using a mixer, beat the butter, brown sugar, and sugar on medium-high until smooth and light. Add in vanilla, egg, and egg yolk. Mix until combined. Scrape the bowl.
Add in the dry ingredients and mix until combined. Add in chopped almonds and chocolate chips. Spread the cookie dough into the pan evenly. Top with extra chocolate chips.
Bake for 40-45 minutes until the edges are set and there is no jiggle in the middle. Immediately, top with the marshmallows. Pack them in. Then, let the cookie bars cool completely in the tin before pulling them out.
Turn the oven to broil on high. Place the entire cookie square on a cookie sheet and place in the oven. If you keep in the original pan the parchment could catch on fire. It will take 1-2 minutes for the marshmallows to brown. Next, cut the bars and top with extra almonds and mini chocolate chips.