Brown Butter Marshmallow Crispy Cookies

Bahan-bahan (20 porsi)

• 1 cup (16 Tbsp; 226g) unsalted butter, cut into 16 pieces
• 2 and 1/4 cups (281g) all-purpose flour (spooned & leveled)
• 2 teaspoons cornstarch
• 1 teaspoon baking soda
• 1/2 teaspoon salt
• 2 cups (52g) crispy rice cereal
• 1 cup (60g) mini marshmallows
• 3/4 cup (150g) packed light or dark brown sugar
• 1/2 cup (100g) granulated sugar
• 1 large egg, at room temperature
• 1 large egg yolk, at room temperature
• 2 teaspoons pure vanilla extract
• optional: flaky sea salt, for topping