How can I incorporate powdered peanut butter into a boxed banana bread?
He's right. It likely would come out with a different consistency. That 1/3 cup of oil and maybe some egg would be partly absorbed by the peanut butter. That will affect the texture.

For a first try: In a separate bowl I would reconstitute the 2 T of peanut butter with water (4 T in this case). For easier measuring 4 T = 1/4 cup.

Add the reconstituted peanut butter to the batter, two options to mix in:


thorougly mix in the peanut butter until it's fully incorporated into the batter
or, swirl it in, kind of like a chocolate marble cake