Preheat the oven to 325°F. Grease a 9x13-inch baking dish with a small amount of butter, ensuring an even coating. Set the prepared dish aside.
In a separate container, melt the butter and allow it to cool slightly.
In a large mixing bowl, use a whisk to beat the eggs until achieving a smooth consistency. Add in the light brown sugar and vanilla extract; whisk to incorporate. Gradually add the slightly cooled melted butter, continuing to whisk until smooth.
Add the flour, cornstarch, baking soda, and salt to the wet mixture. Whisk the ingredients together until just combined, making sure not to overmix.
Gently fold the white chocolate chips and chopped pecans into the batter until evenly distributed.
Pour the batter into the baking dish.
Bake in the preheated oven for about 25 to 30 minutes or until the blondies are golden and a skewer inserted in the middle comes out mostly clean. Remove from the oven and let the blondies cool completely before slicing (2 to 3 hours or overnight).
After the cooling period, use a knife to carefully slice the blondies into squares and serve.