Preheat the oven to 350°F (180°C). Line a 9x9 pan with parchment paper and set aside.
In a large microwave safe bowl, melt the butter.
1 cup (222g) salted butter, melted
To the bowl with the melted butter, whisk in the brown sugar and granulated sugar.
1 1/4 cup (308g) brown sugar, 1/4 cup (58g) granulated sugar
Once mixed in, whisk in the eggs and cake batter flavoring.
1 tsp cake batter flavoring, 2 eggs
Add the flour, cornstarch, salt, white chocolate chips and sprinkles to the bowl and fold in.
2 1/4 cup (342g) all-purpose flour, 1 Tbsp corn starch, 1/2 tsp salt, 1/2 cup (100g) white chocolate chips, 1/2 cup (107g) red, white, and blue sprinkles
Spread the dough into the prepared pan.
Bake at 350°F (180°C) for 23-27 minutes or until the inside temp reaches at least 160°F and a toothpick comes out with a few moist crumbs on it.
Allow the blondies to cool completely before cutting. Enjoy!