Method
1. Adjust oven rack to middle position; heat oven to 350° F (~175 C)
2. Spread nuts on large rimmed baking sheet and bake until deep golden brown, 10 to 15 minutes
3. Transfer nuts to cutting board to cool; chop coarsely and set aside
4. While nuts toast, line a 13 by 9-inch baking pan with foil, leaving enough overhang to help you lift the blondies from the pan when they're done
5. Grease foil-lined pan with butter or oil
6. Whisk flour, baking powder, and salt together in medium bowl; set aside
7. Melt unsalted butter in microwave - low heat
8. Whisk melted butter and brown sugar together in large bowl until combined
9. Add eggs and vanilla and mix well
10. Using rubber spatula, fold dry ingredients into egg mixture until just combine
11. Fold in chocolate and nuts
12. Turn batter into prepared pan, smoothing top with rubber spatula
13. Bake until top is shiny, cracked, and light golden brown, 22 to 25 minutes
14. Cool on wire rack to room temperature
15. Remove bars from pan by lifting foil overhang and transfer to cutting board