Preheat the oven to 350 F. In a large bowl, whisk together flour, sugar, cocoa powder, salt, and baking soda. Add in eggs, melted butter, and vanilla extract and mix until smooth.
In a medium bowl, whisk together flour, salt, and baking soda. In a large bowl, combine butter and sugar until fluffy. Add in 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. Pour the brownie batter into a greased 8-inch square baking dish.
Evenly top the brownie batter with the cookie dough. Bake for 25-30 minutes.
