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. Whisk until smooth. Pour the brownie batter into a greased 8-inch square baking dish.
In a medium bowl, whisk together flour, oats, salt, and baking soda. In a large bowl, combine butter with both sugars until fluffy. Add in the egg and vanilla extract, and mix until smooth.
Add in the flour mixture, and mix until the flour is fully combined. Evenly spread the cookie dough over the brownie batter. Bake for 25-30 minutes.
