Beat butter with sugars in standing mixer until light and fluffy, about 2 full minutes. Beat in eggs, then vanilla.
In a separate bowl, whisk together flour, oat flour, salt, baking powder and baking soda. Add to butter mixture with mixer speed on low until well incorporated. Beat in remaining ingredients (reserving some chocolate and pumpkin seeds for topping, if desired) until just combined.
Roll dough by 2 tablespoonful-sized balls between hands and place 3" apart on baking sheet. Flatten balls slightly with your palm, then top with a piece of chocolate and a few pumpkin seeds, if desired.
Bake for about 8 minutes, until golden at edges but slightly underdone in the middle. Cool on pans for 2 minutes then transfer to wire racks to cool completely.