Servings 2dozen cookies (more or less depedning on how large you roll them)
2sticks (8 ounces, 1 cup) unsalted butter, at room temperature
1and 1/2 cups light brown sugar, packed
1large egg yolk, at room temperature
2and 1/2 cups rolled oats (not instant oats)
2cupssemi-sweet chocolate chips
Preheat oven to 350 (F). Line two large baking sheets with parchment paper; set aside.
In the bowl of a stand mixer fitted with the paddle attachment, or in a large bowl using a handheld electric mixer, cream together the butter and both sugars until light and fluffy, about 3 minutes. Beat in the pumpkin. Add in the egg yolk and the vanilla extract until combined.
In a medium bowl, stir together the flour, baking soda, baking powder, salt, and spices. On low speed, gradually beat the flour mixture into the butter/sugar mixture until just incorporated. Turn mixer off. Using a wooden spoon or strong spatula, stir the oats and chocolate chips into the cookie dough, stirring just until incorporated.
Scoop 2-inch balls of cookie dough onto the prepared baking sheets, leaving about 1 and 1/2 inches between so they have room to spread.
Bake, one sheet at a time, in preheated oven for 12 to 15 minutes, or until cookies are golden and set at the edges and still just slightly soft in the center. Repeat with all cookie dough.
Cool cookies on baking sheet for 20 minutes before transferring them to a wire rack to cool completely.