Walnut and Chocolate Chip Blondies (recipe from Martha Stewart)

8 tablespoons (1 stick) unsalted butter, melted, plus more for pan
1/2 cup packed light-brown sugar
1/3 cup granulated sugar
1 large egg
1 teaspoon pure vanilla extract
1 cup all-purpose flour, (spooned and leveled)
1 teaspoon salt
1 cup semisweet chocolate chips
1 cup chopped walnuts

Preheat oven to 350 degrees. Brush an 8-inch square baking pan with butter; line pan with a piece of parchment paper, leaving a 2-inch overhang on two sides. Butter paper.

In a large bowl, whisk butter and sugars until smooth. Whisk in egg and vanilla. Add flour and salt; mix just until moistened (do not overmix). Fold in 1/2 cup each chocolate chips and walnuts.

Transfer batter to prepared pan; smooth top. Sprinkle with remaining chocolate chips and walnuts.

Bake until top is golden brown and a toothpick inserted into the center comes out clean, 40 to 45 minutes [I took it out after ~30 minutes and it was well done]. Set pan on a wire rack, and let cool completely. Using parchment overhang, lift cake from pan and transfer to a cutting board; cut into 16 squares.