Whisk together flour, baking powder, salt, and cinnamon in large mixing bowl.
In separate bowl, cream butter until light and fluffy. (I didn't bother pulling out the mixer here, and just hand-whisked everything.)
Add sugar and eggs to the butter and mix well.
Peel bananas, then chop into coins and add to the egg mixture and whisk until just mixed in.
Stir in dry ingredients until just mixed.
Stir in walnuts, then pour batter into greased loaf pan.
Bake for about 60 minutes at 350 degrees, or until knife inserted in middle of loaf comes out clean.
Cool in pan for about 10 minutes, then remove from pan and let cool as much as you can stand it before slicing.
We originally used just 1/2 tsp cinnamon in this recipe, but upped it to 1.5 tsp in subsequent batches. It's so much better that way that I've changed it up in the ingredient list, and I also highly recommend adding chocolate chips. :)
Kid-Friendly Banana Bread from Mashup Mom: https://www.mashupmom.com/kid-friendly-banana-bread/