Step 1

Preheat the oven to 400 degrees Fahrenheit (205°C) and lightly grease or line a cookie sheet with parchment paper.

Step 2

Make the filling: Combine the butter, powdered sugar, and vanilla extract in a large bowl. Stir to combine, then beat with an electric mixer on low until smooth and fluffy.

Step 3

Add the marshmallow creme and beat on low or mix by hand until well blended.

Step 4

Cover the filling and place it in the fridge to chill.

Step 5

Make the cookies: Put the softened butter and white sugar in a large bowl. Beat with an electric mixer on low-medium speed until well blended and pale.

Step 6

Add the egg, evaporated milk, and vanilla, and mix on low until smooth.

Step 7

Combine the flour, salt, cocoa powder, baking soda, and baking powder in a separate bowl. Whisk by hand to distribute the leavening agents.

Step 8

Add the dry mix to the wet and gently mix by hand with a spatula. Stop stirring when no streaks of flour are visible.

Step 9

Use a tablespoon or small cookie scoop to portion the cookie dough onto the baking sheet, leaving at least 3 inches between each.

Step 10

Bake until the edges are firm when pressed (approximately 6-8 minutes). Remove the tray from heat and let them cool for 1-hour (minimum).

Step 11

To assemble: Take the filling out of the fridge and mix with a wooden spoon or spatula until smooth.

Step 12

Flip half of the cookies and pipe or spoon 1-2 tablespoons of filling onto the flat side.

Step 13

Add a second cookie on top to make a sandwich, and gently press to ensure they're stuck.

Step 14

Serve and enjoy!