Preheat oven to 350 degrees F. Grease an 8-inch square pan. Line with parchment paper.

Melt butter in microwave safe bowl. Stir in sugar, eggs, and vanilla. Beat in cocoa, flour, salt, and baking powder. Spread batter into prepared pan.

Bake in preheated oven for 12 minutes. Remove from oven and let sit for 5 minutes. After 5 minutes place in the refrigerator for 15 minutes to cool.

Meanwhile with your stand mixer, cream together butter and brown sugar. Beat in vanilla and salt. Gradually add flour. The mixture will be crumbly. Add in 2 tablespoons of milk and mix to combine. Add additional tablespoon if it's too dry. Stir in mini chocolate chips.

Spread cookie down very carefully over cooled brownie layer.

Bake in oven for 25 minutes. Remove from oven and arrange pretzels carefully on top of cookie dough. Return to oven and bake for another 15 minutes or until cookie dough is lightly browned and cooked through.