Blondie Swirled Brownies

Ingredients

• 1 1/3 cups all-purpose flour - divided (⅔ + ⅔ )
• ½ tsp salt - divided
• 1 tbsp unsweetened cocoa powder
• 4 oz semi-sweet chocolate, roughly chopped
• ½ cup unsalted butter, cut into small cubes - divided ( ¼ cup for each chocolate)
• 1 ½ tsp instant espresso powder - (optional)
• 1 cup granulated sugar - divided
• 4 eggs, at room temperature, lightly beaten - divided (2 + 2)
• 1 tablespoon vanilla extract - divided
• ¼ cup semi sweet chocolate chips