Preheat your oven to 350 degrees. Line a baking sheet with a silicone mat or parchment paper and set aside.
Using a handheld mixer, beat together the butter and both sugars until light and fluffy.
Add in the egg and vanilla; beat together.
Next, add in the flour, baking soda, baking powder, cinnamon, and oats. Beat on low speed until combined.
Stir in the cranberries and pistachios.
Use a tablespoon measure and place mounds of cookie dough about 2 inches apart on the baking sheet. Press them slightly with your hand, or you can use a fork like you would do with a classic peanut butter cookie. (I sprinkle a few cranberries and pistachios on top before baking, just for a prettier cookie. It's completely optional.)
Bake for 12 minutes. Allow cookies to cool on the baking sheet for 2-3 minutes before transferring them to a wire cooling rack to finish cooling completely.