Preheat the oven to 375°F. Lightly grease two baking sheets, or line them with parchment paper.

Whisk together the flour, baking powder, soda, salt, and spices in a medium bowl.

In a separate bowl, beat together the butter and sugars. Scrape down the sides of the bowl, and beat briefly, just until smooth.

Add the pumpkin, eggs, vanilla, and orange zest, beating to blend.

Slowly add the dry ingredients, beating to blend. Stir in the chocolate chips and walnuts.

Using a tablespoon cookie scoop or soup spoon, drop the dough onto the prepared baking sheets in 1 1/4" balls. Bake them on the middle oven rack for about 18 minutes, until the edges are lightly browned. Remove the cookies from the oven, and let them cool on the baking sheets 5 minutes before transferring them to racks.

If desired, press two chocolate chips into each warm cookie to make eyes for the pumpkin.

Stir together the sugar, milk and vanilla until the glaze is smooth. Dip the tops of the cookies in the glaze; or drizzle the glaze over the cookies.

Place the cookies back on the rack for the glaze to set. Wrap loosely, and store for several days at room temperature; freeze for longer storage.