One-Bowl Blondies

Gather the ingredients. Position a rack in the center of the oven and heat to 350 F.

Grease an 8 by 8-inch pan with butter. Line it with a long sheet of parchment paper that extends up and over the two opposite sides of the pan.

Whisk 1/2 cup (4 ounces) unsalted butter, melted and cooled , 2/3 cup packed (133 grams) light brown sugar , 1/3 cup (67 grams) granulated sugar , and 2 teaspoons pure vanilla in a large bowl for 30 seconds.

Whisk in 1 large egg .

Sprinkle 1/2 teaspoon baking powder and 1/2 teaspoon fine salt over the bowl, one at a time, vigorously whisking after each.

Gently fold in 1 cup (130 grams) all-purpose flour , until just a few streaks remain, and then 1/2 cup toasted, coarsely chopped pecans , if using, and 1/2 cup semi sweet chocolate chips , if using. Do not over-mix.

Scrape the batter into the prepared pan and smooth the top. It will be very thick.

Bake until the top is lightly browned and crackly, the edges are starting to pull away from the sides of the pan, and a wooden skewer inserted in the center comes out with wet crumbs, 24 to 27 minutes. Let cool on a rack to room temperature.

Lift the blondies out of the pan by the parchment paper overhang, slice, and serve.