Preheat oven to 350°F with racks in top third and lower third positions. Line 2 large baking sheets with parchment paper. Melt ¾ cup butter in a small saucepan over medium heat. Cook, stirring and swirling the pan occasionally, until nutty and golden brown, 8 to 10 minutes. Pour into a large heatproof bowl; refrigerate, uncovered, until cooled, about 15 minutes.

Meanwhile, whisk ¾ cup all-purpose flour, ¾ cup whole-wheat flour, ¾ cup oats, 2 teaspoons pumpkin pie spice, 1 teaspoon baking soda, ¾ teaspoon salt and ½ teaspoon baking powder together in a medium bowl.

Add 1 cup brown sugar to the cooled melted brown butter; whisk until combined (the mixture will not be smooth). Add ½ cup pumpkin, 1 egg yolk and 2 teaspoons vanilla; whisk until smooth. Add half of the flour mixture to the butter mixture; fold until just combined. Add ¾ cup chocolate chips and the remaining flour mixture; fold until just combined.

Using a 1½-ounce (3-tablespoon) cookie scoop, scoop the dough onto the prepared baking sheets, spaced at least 1 inch apart; press gently with your palm to flatten slightly. Bake until the cookies have spread slightly and are golden brown around the edges and bottom, 10 to 14 minutes, rotating the pans from the top to bottom racks halfway through. Let cool on the pans for 5 minutes. Serve warm or transfer the cookies to a wire rack to cool completely, about 20 minutes. Recipe developed by Marianne Williams