The costco natural stuff is a fine consistency if you store it in the fridge. Just peanuts and salt, I believe. While it's new, keep it at room temp. Then when you open it, give it a good stir (a long iced tea spoon or butter knife will work), and pop it in the fridge for future uses.
We actually don't eat much PB&J, but we like it with apples, bananas, and celery, as an ice cream topping, and I've been meaning to add it to smoothies. On toast an bagels sprinkled with cocoa powder! DH eats primarily grain free, so he just eats it straight off the spoon. It goes fast in our house. I think it would probably be good in yogurt and oatmeal, too.