Preheat your oven to 350°F (175°C).

Brown the butter in a saucepan over medium heat until it turns golden and has a nutty aroma.

In a mixing bowl, combine the brown butter and granulated sugar, whisking until smooth.

Add the egg and vanilla extract, mixing until fully combined.

In a separate bowl, whisk together the flour, baking soda, salt, cornstarch, and lemon zest.

Gradually add the dry ingredients to the wet ingredients, stirring until just combined.

Fold in the fresh blueberries and white chocolate chips, being careful not to overmix.

Chill the dough in the refrigerator for at least 30 minutes.

Scoop the dough onto a prepared baking sheet, leaving some space between each ball.

Bake for 10-12 minutes or until the edges are set and golden. The centers will look underbaked.

Remove from the oven and let them cool on the baking sheet for a few minutes before transferring to a wire rack.