Step 1

Preheat the oven to 350°F (177°C). Grease a 9-inch square pan or line with parchment paper, leaving an overhang on the sides to lift the finished blondies out (makes cutting easier). Set aside.

Step 2

Whisk the flour, baking powder, and salt together in a large bowl.

Step 3

In a medium bowl, whisk the browned or melted butter and brown sugar together. Once completely combined, whisk in the whole egg, egg yolk, and vanilla extract until combined. Pour the wet ingredients into the dry ingredients and whisk or stir until combined. Batter is pretty heavy and thick, so I usually use a rubber spatula. Fold in the butterscotch morsels and nuts, if using.

Step 4

Evenly spread batter into prepared pan. Bake for about 30-35 minutes, or until a toothpick comes out *mostly* clean. A couple moist crumbs are ok, as long as it’s not wet. Remove from the oven and cool blondies completely in the pan set on a wire rack.

Step 5

Cover and store leftover blondies at room temperature or in the refrigerator for up to 1 week.