Preheat the oven to 370°F (188°C). Line a 9x9-inch baking pan with aluminum foil and spray the foil with non-stick cooking spray; set aside.
In a medium bowl, whisk together the flour, baking soda, and salt until evenly combined; set aside.
In a large bowl, beat the softened butter, granulated sugar, brown sugar, and vanilla extract with an electric mixer until light and creamy, about 2–3 minutes.
Add the eggs one at a time, mixing well after each addition until fully incorporated.
Fold the dry flour mixture into the wet ingredients until just combined; avoid overmixing.
Stir in the 1 1/2 cups white chocolate chips with a spatula until evenly distributed.
Press the batter evenly into the prepared pan, then sprinkle additional chocolate chips on top as desired.
Bake for 20–23 minutes, or until the edges are lightly golden and a toothpick inserted near the center comes out with a few moist crumbs.
Allow the blondies to cool completely in the pan on a wire rack, then lift out using the foil and cut into 12 bars.