Position rack in middle of oven. Preheat oven to 350°F/180°C. Coat a 9-inch (23 cm) square pan with nonstick spray, line with a strip of parchment paper to cover the bottom and overhang on two sides; spray the parchment paper as well.

Whisk the flour, baking soda and salt together in a small bowl to aerate and combine; set aside.

Place butter in small pot, melt over low-medium heat and continue to cook until browned. Pour into heatproof mixing bowl. Whisk in brown sugar, pumpkin purée, pumpkin spice and espresso powder. Allow to cool. Whisk in egg and vanilla until combined. Fold in flour mixture until a few streaks of flour remain, then add chips and fold together well. Scrape batter into prepared pan.

Bake for about 30 to 35 minutes or until a toothpick inserted in the center comes out with a few crumbs clinging and the edges are just coming away from the sides of the pan. Cool on rack. Use overhanging parchment to lift blondies out of pan. Peel away parchment and cut into a 5 by 5 grid into 25 blondies. These Pumpkin Spice Mocha Latte Blondies are best the day and day after they are baked. They may be stored wrapped airtight for up to 3 days.