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.
Pour the brownie batter into a greased 8-inch square baking dish. Evenly top with the strawberry topping and swirl with a knife. Bake for 25-30 minutes.