Combine 3/4 cup of room temperature butter with 1/2 cup of granulated sugar and 1/2 cup of brown sugar in a large bowl and use an electric hand mixer to blend until creamy
Add 1 large egg, 1 egg yolk and 1 teaspoon of vanilla extract and blend until light and fluffy
Add 1/3 cup of natural unsweetened cocoa powder, 1 teaspoon of espresso powder, 3/4 teaspoon of baking soda and 1/2 teaspoon of salt and mix on slow speed until just combined
Add 1 2/3 cups of all purpose flour and mix until just combined using a silicone spatula
Gently fold in 4 ounces of chopped almonds and 3/4 cup of milk chocolate chips until evenly distributed
Swirl some of the marshmallow fluff into a portion of the cookie down leaving visible swirls throughout
Scoop heaping tablespoons of cookie dough onto parchment lined or non-stick baking sheets
Transfer the cookie dough balls into the freezer for 10 minutes to allow the marshmallow fluff to set
Preheat your oven to 350 degrees
Bake the chilled dough balls several inches apart for 10-11 minutes
Transfer the baking sheets onto cooling racks to allow the cookies time to set before transferring them directly onto the cooling racks
Swirl the warm cookies inside of a large round dough cutter to round them out if desired
Enjoy
Store leftovers in an airtight container at room temperature