I made these with smooth peanut butter because that's what I happened to have. The taste is great, but I think the texture would be much better with crunchy peanut butter.
Use a smaller bowl to weigh/measure out the flour, oats, bicarb and salt. Mix them together and set aside.
Use an electric hand whisk to beat the peanut butter, banana and sugar together in the larger bowl.
Beat in the egg and vanilla extract.
Mix in the flour mixture. It will make a very sticky dough.
Line some baking trays - I fit 12 cookies per tray and cook them in batches.
Use 2 teaspoons to portion the dough into balls - don't try and roll it in your hands because you'll end up in a very sticky mess! Use a wet fork to flatten the dough down onto the baking trays. Keep wetting the fork to prevent sticking to the dough.