Here's a good place to start. Get the following:
1 cup natty PB
1 cup oats (optional)
4-6 TBSP cream (optioanl)
1/2 cup water (to start)
Put protein powder into a mixing bowl. Pop the natty PB in the microwave for a maybe 20-30 seconds. It will mix into the protein much better this way. Then either add your oats whole or blend them up into a powder first. Add your wet ingredients. If you opt for the higher fats add less water to start. Then add your water. Mix it up really well. If it is too dry add a bit more water until you can get a firm paste-like consistency. Spoon your mixture into a small pan and make sure to coat it evenly. Pop it in the fridge over night. Cut it after it has solidified into equal portions and your good to go. Wrap them up in foil or cerran wrap. You can also use the option of divying up the ingredients into single serving amounts, and then instead of putting them into a pan to put in the fridge, put them right into foil or cerran wrap and refrigerate them. Either way you can't go wrong.