Confetti Skillet Cookie

 

1½ sticks (6 ounces/170g) unsalted butter, at room temperature, plus more for the pan

2 ounces (55g) cream cheese, at room temperature

¾ cup (150g) granulated sugar

¼ cup (50g) packed light brown sugar

1 large egg

2 teaspoons vanilla extract

1 teaspoon kosher salt

¼ teaspoon baking soda

2 cups (256g) all-purpose flour

⅓ cup (65g) rainbow sprinkles (not the round kind)

 

4 tablespoons (½ stick/57g) unsalted butter, at room temperature

1 cup (120g) powdered sugar

1 to 2 tablespoons heavy cream or milk

1 teaspoon vanilla extract

Pinch of kosher salt

1 tablespoon rainbow sprinkles, or more if you want!

 

Make the cookie: Arrange a rack in the center of the oven and preheat the oven to 350°F. Lightly butter a 9- or 10-inch ovenproof skillet. In a large bowl, with an electric mixer on medium-high speed, mix the butter, cream cheese, granulated sugar, and brown sugar until creamy, 5 to 7 minutes. Add the egg, vanilla, and salt and mix until well combined. Stir in the baking soda, then fold in the flour and sprinkles with a flexible spatula until just combined. Press the dough evenly into the baking pan. Bake, rotating the pan halfway through, until golden but still soft in the center, 22 to 25 minutes. Set the pan on a wire rack and cool the cookie completely in the pan. Make the frosting: In a large bowl, use an electric hand mixer on medium speed to beat the butter until creamy. Add the powdered sugar, 1 tablespoon of the cream, the vanilla, and salt and mix on low until the sugar is moistened. Turn the mixer up to high and mix the frosting until light and fluffy, 5 to 7 minutes. If the mixture is dry and hard to work with, add the additional tablespoon cream. Spread the frosting over the cooled cookie and top with as many sprinkles as you like. (The cookie can be stored, covered, at room temperature for up to 4 days.)