Preheat oven to 325 degrees. Line two sheet pans with parchment
paper and set aside. In a small mixing bowl, sift together flour,
baking soda and salt. In a separate mixing bowl, cream together
butter and peanut butter. Add both sugars and mix until combined
and fluffy. Add in egg yolk and vanilla and mix until combined. Add
in the mashed banana and mix to combine. Add half of the dry
ingredients and mix to combine then add in the rest, again mixing
to combine. Fold in the chocolate chips with a wooden spoon.
Form the dough into 1.5 inches balls and place on the prepared
sheet pans at least 2 inches apart. Bake for 12 Ė 14 minutes or until
the edges are golden brown and the middles are still soft. DONíT
OVER COOK. Remove from the oven and cool on the pans on wire
racks then transfer to wire racks to cool completely before storing.