Follow these easy steps to create your Irresistible Brownie Cookie Dough Sandwich Cookies:

For the Brownie Cookies:

1. Preheat Oven: Preheat your oven to 350°F (175°C). Line two baking sheets with parchment paper.
2. Mix Wet Ingredients: In a large bowl, combine the melted butter, granulated sugar, and brown sugar. Mix well until fully blended.
3. Add Eggs and Vanilla: Add the eggs one at a time, mixing well after each addition. Stir in the vanilla extract.
4. Combine Dry Ingredients: In another bowl, whisk together the flour, cocoa powder, salt, and baking powder.
5. Mix Together: Gradually add the dry ingredients to the wet mixture, stirring until just combined.
6. Scoop Cookies: Using a cookie scoop or tablespoon, drop rounded balls of the brownie batter onto the prepared baking sheets, spaced about 2 inches apart.
7. Bake: Bake in the preheated oven for 12-15 minutes or until the edges are set and the center looks slightly underbaked.
8. Cool: Allow the cookies to cool on the baking sheets for 5 minutes before transferring them to wire racks to cool completely.

For the Cookie Dough Filling:

9. Mix Butter and Sugar: In a medium bowl, beat the softened butter and brown sugar until creamy and smooth.
10. Add Condensed Milk and Vanilla: Mix in the sweetened condensed milk and vanilla extract until well combined.
11. Incorporate Flour: Gradually add the flour, mixing until fully incorporated.
12. Fold in Chocolate Chips: Gently fold in the mini chocolate chips until evenly distributed.

Assemble the Sandwich Cookies

13. Fill Cookies: Once the brownie cookies are completely cooled, spread a generous amount of cookie dough filling on the flat side of one cookie. Top with another brownie cookie, flat side down, to create a sandwich.
14. Repeat: Continue this process until all brownie cookies are filled and paired.