Preheat a camp oven to 400 degrees F (200 degrees C). Line the muffin trays with paper liners.
In a large bowl mash the bananas with a fork until smooth.
Add the peanut butter and continue to mash with the fork as much as possible to make sure it breaks up and combines with the bananas. Tip: Peanut butter does not like to mix with other ingredients. Make sure it combines well with the bananas before adding additional ingredients.
Add the baking soda, eggs, and vanilla, then mix well to create a well-blended mixture.
Divide the mixture evenly amongst the prepared paper-lined muffin trays. Bake in the preheated camp oven for 15 minutes or until brown.
Remove the cooked muffins from the camp oven then let rest for 5 minutes before removing from the tin and placing them on a cooling rack.