Preheat oven to 350 degrees and line an 8×8 inch baking dish with parchment paper sprayed with non-stick cooking spray.
Place butter into a microwave safe bowl and microwave for 30-45 seconds until butter is melted and hot.
Add 3/4 cup white chips and let sit for 1 minute. Stir until smooth, if needed place back in microwave for an additional 15-30 seconds to melt through.
Place flour, sugar, baking soda and salt into a large mixing bowl. Stir to combine.
Stir in eggs, oil and melted white chocolate. Stir until well combined then stir in chips.
Transfer to prepared baking dish, spreading evenly. Bake for 40-45 minutes, until cooked through.
Let cool completely then drizzle with melted chocolate if desired and cut into squares. Serve warm, room temperature or chilled.