Old baking powder doesn’t perform well; while it will still give baked goods some rise, it may not be enough. And, you can’t just add extra baking powder to boost its leavening power ...
You can make your own baking powder by combining 15ml/1tbsp bicarbonate of soda with 30ml/2tbsp cream of tartar. Measure carefully as too much or too little can upset a recipe’s balance.
but not baking powder, which is a combination of baking soda and cream of tartar) is a perennial hack, associated as much with old housewives as with TikTok videos, health sites and even the Great ...