Step 1
Preheat oven to 350 degrees F (175 degrees C). Grease a 12x18-inch pan with cooking spray.
Step 2
Combine 1 cup pepper-type soda and 1 cup butter in a saucepan over medium-low heat; heat until butter is melted 3 to 5 minutes. Remove from heat and let cool.
Step 3
Place bacon in a large skillet and cook over medium-high heat turning occasionally until evenly browned about 8 minutes. Drain on paper towels.
Step 4
Mix flour white sugar 1/4 cup cocoa powder cinnamon and salt together in a large bowl.
Step 5
Whisk buttermilk vanilla extract and baking soda together in a small bowl. Pour flour mixture; mix until batter is blended. Add butter mixture 1/3 of the bacon and chocolate chips; mix thoroughly. Spread in the prepared pan.
Step 6
Bake in the preheated oven until top is dry and edges have started to pull away from the sides of the pan 25 to 30 minutes.
Step 7
Combine 6 tablespoons pepper-type soda 1/2 cup butter and 3 tablespoons cocoa powder in a saucepan; bring to a boil. Remove from heat. Add 1/2 of the remaining bacon and confectioners' sugar; whisk until frosting is smooth.
Step 8
Spread frosting over brownies. Garnish with remaining bacon. Cool until frosting sets about 20 minutes. Cut into squares.