I'm sure you never find yourselves without basic ingredients, I know it's never happened to me, especially not when I was making banana bread, never ever.
Luckily, you can make your own baking powder.
Ingredients: baking soda, cornstarch, and cream of tartar.
Mix 2 teaspoons of cream of tartar
with 1 teaspoon of baking soda
and 1 teaspoon of cornstarch.
Mix it all together
And add it to your recipe in the amount it calls for of baking powder.
Of course it's much easier to just have a couple of extra containers of baking powder on hand---but if you run out and going to the store isn't an option, here's your solution: make your own!
Happy Holiday baking!
2 tsp cream of tartar
1 tsp baking soda
1 tsp cornstarch