In a medium bowl, whisk together the flour, cocoa powder, baking soda, and salt until well combined.

In a separate large bowl, beat the softened butter with brown sugar and white sugar until fluffy and light in texture. Add the egg and vanilla extract and continue beating until fully incorporated.

With the mixer on low speed, gradually beat the dry flour mixture into the butter mixture, about half at a time. Fold in the chocolate chips gently until evenly distributed throughout the dough.

Cover the bowl with plastic wrap and refrigerate for at least 3 hours or preferably overnight to firm up the dough for easier shaping.

Preheat the oven to 350°F (175°C) and line cookie sheets with parchment paper.

Shape the chilled dough into balls about 1 to 1.5 tablespoons each and place them on the prepared baking sheets, spacing each about 2 inches apart.

Bake in the preheated oven for 8 to 10 minutes, until the tops look set but not dry. Remove from oven and allow cookies to cool completely on the baking sheet.

Add raspberries to a blender or food processor and pulse until smooth. Strain the puree through a fine metal sieve, removing seeds.

Transfer the seedless puree to a small saucepan over low heat. Stir gently and bring to a gentle boil, reducing until thick like jam. Remove from heat and allow to cool completely.

In a large bowl, beat the softened butter until smooth. Add the cream cheese and beat until fully combined and creamy.

With the mixer on low speed, gradually mix in about 1 cup of powdered sugar and salt until incorporated.

Add 1 tablespoon of the cooled raspberry puree to the frosting mixture and mix well. Gradually add the remaining powdered sugar in 1/2 cup increments, mixing in an additional tablespoon of the raspberry puree as needed until the frosting reaches desired consistency.

Spread about 1 tablespoon of raspberry cream cheese frosting on the bottom side of one cookie, then top with a second cookie to form a sandwich.