Combine flours, oats, baking soda, cinnamon and salt in a medium bowl. Stir and set aside.
In large bowl of an electric mixer add melted butter and sugars. Beat on medium speed for 2 minutes.
Add egg, vanilla, pumpkin puree and milk. Continue beating until combined.
On low speed add dry mixture until just combined.
Add chocolate chips. Let cookie dough rest for 30 minutes.
Preheat oven to 350°F. While oven is heating portion cookie dough on parchment lined cookie sheet. For regular round cookies use a 3 tablespoon scoop. For big Jack-o'-lanterns use an ice cream size scoop (½ cup). Using a bit of flour if needed, flatten into a large pumpkin shape. Add a bit of dough at the top for the stem.
Bake cookies in 350°F oven for 20-22 minutes, slightly longer for large pumpkins.
Allow cookies to cool for a few minutes before transferring to a wire rack. Cool completely before decorating or storing.
Decorate with icing, chocolate chips, candy corn or candy eyes. Makes 26 regular cookies or 13 large Jack-o'-lanterns.