substitute each teaspoon (5 grams) of baking powder in the recipe with 1/4 teaspoon (1 gram) baking soda and 1/2 teaspoon (2.5 grams) vinegar. summary: each teaspoon (5 grams) of baking powder can be replaced with a 1/4 teaspoon (1 gram) baking soda and a 1/2 teaspoon vinegar.