Preheat the oven to 350 F. Line a 12 cup muffin pan with paper liners. In a large bowl, whisk together flour, sugar, cocoa powder, salt, and baking soda together. Add in the melted butter, eggs, and vanilla extract and mix until smooth.
In a medium bowl, whisk together flour, salt, and baking soda. In a large bowl, combine butter with peanut butter and sugar until fluffy. Add in egg and vanilla extract, and mix until smooth. Add in the flour mixture, mix until it is fully combined. Fold in the sprinkles. In a shallow dish, combine granulated sugar with ground cinnamon.
Roll the cookie dough into balls, and roll each one into the cinnamon sugar mixture. Evenly divide the brownie batter between the muffin cups. Place the cookie dough on top of each brownie cup. Bake for 20-25 minutes.
