Trying to figure out how to convert standard recipes to Passover recipes is confusing and often does not work because baking (and sometimes cooking too) is like chemistry and the balance of ingredients really impacts the final product. Too much of this or too little of that can completely ruin a dish. So for a few conversion tips I asked my friend Paula Shoyer to share an excerpt from her book the Jewish Holiday Baker. Below she gives her scientific, tested and perfected conversions for important baking substitutions. I would also recommend sticking to recipes that do not have large amounts of ingredients to convert. For example, cookies with 2 ½ cups of flour, even if converted properly, will be too dense with that much matzo cake meal. Stick to recipes that have less than 1 cup of flour or ½ cup of corn syrup to substitute.
Substitution Rules for Converting Recipes
1 cup (125g) flour = ¾ cup (120g) potato starch plus ¼ cup (33g) matzoh cake meal
1 tablespoon flour = ½ tablespoon potato starch
1 tablespoon cornstarch = 1 tablespoon potato starch
1 cup (120g) confectioners’ sugar = 1 cup (200g) minus 1 tablespoon granulated sugar plus 1 tablespoon potato starch pulsed in a food processor or blender until it becomes a very fine powder
½ cup (120ml) corn syrup = 2/3 cup (130g) granulated sugar plus ½ cup (120 ml) water boiled for 2 to 3 minutes or until it starts to thicken and left to cool. Store in a jar or container.
1 cup vanilla sugar = 1 cup (200g) granulated sugar plus 1 split vanilla bean left to sit for 24 hours in a tightly covered jar
1 teaspoon cream of tartar = 1 ½ teaspoons lemon juice or 1 ½ teaspoons vinegar