Any reason why you would like to substitute the peanut butter? If it is due to nut allergy, you can try using sun butter instead. If you prefer other taste, you can try almond butter. These should work as well. :)
If you are looking for a nut-free yet nutty and creamy substitute, maybe you can try sunflower seed butter. It is the closest to peanut butter in terms of taste and flavour. Plus, it's a wee bit healthier too:)
You can use coconut cream to make the sauce creamy and rich and just add ground peanuts to still have the "peanutty" taste.