Peaches and Cream Blondies

Preheat oven to 325 degrees F. Line a greased 8-inch square baking pan with parchment paper, allowing a 2-inch overhang of paper. Grease parchment paper; set pan aside.

Whisk together 1 2/3 cups flour, the baking powder, and salt in a medium bowl, and set aside.

Put 9 tablespoons of butter and the brown sugar in the bowl of an electric mixer fitted with the paddle attachment; mix on medium speed until pale and fluffy, about 3 minutes. Add 2 eggs and 1 teaspoon vanilla; mix until combined. Reduce speed to low. Add flour mixture, mix, scraping down sides of bowl, until well combined. Transfer to a large bowl.

Put cream cheese, 1/4 cup granulated sugar, remaining 2 tablespoons butter, remaining 2 tablespoons flour, remaining egg, and remaining 1/2 teaspoon vanilla into the clean bowl of an electric mixer fitted with the paddle attachment; beat on medium speed until just smooth. Fold in the diced peach.

Pour half the blondie batter into the prepared pan, and spread evenly with an offset spatula. Spoon two-thirds of the cream-cheese mixture on top, and spread evenly. Drop dollops of remaining blondie batter on top (spacing about 1 inch apart), and spread. Top with dollops of remaining cream-cheese mixture, about 1 inch apart. Gently swirl cream cheese mixture into batter with a butter knife, running the knife lengthwise and crosswise through layers.

Place pan into the preheated oven and bake until golden brown and a cake tester inserted into center comes out with a few crumbs but is not wet, about 45 minutes. Let cool completely on a wire rack before lifting the bars out of the pan (using the parchment paper overhang) and cutting into squares.

Adapted from Martha Stewart Cookies.