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. Add in eggs, melted butter, and vanilla extract until smooth.
In a medium bowl, whisk together flour, salt, and baking soda. In a large bowl, combine butter with sugar until fluffy. Add egg and vanilla extract, and mix until smooth.
Add in the flour mixture, and mix until it is fully combined. Fold in the Christmas sprinkles. Evenly divide the brownie batter between the prepared muffin pan.
Evenly top each brownie batter with the cookie dough. Bake for 15-20 minutes.
