Baking soda is a base. That’s all it is. When it meets an acid and some liquid, it throws a tiny chemical party that releases carbon dioxide gas. Those bubbles are what make your cake rise, not fairy wings.
So, if you don’t have the base, you need a different chemical dance partner. The good news? You probably have half a dozen acids hiding in your fridge right now, sipping a coffee and laughing at your panic.