Baking PowderMade from Cream of tartar and starch, baking powder is a leavening agent, which causes your batter to rise. It has a built-in acidic ingredient, so you don’t need to add anything else (unlike with baking soda). Too much baking powder results in a bitter tasting product, while too little results in a tough cake with little volume.
Baking SodaBaking soda is pure sodium bicarbonate, and needs to be paired with an acidic ingredient like honey, chocolate, or yogurt. Like baking powder, it’s a leavening agent. Use too much, and you’ll have a soapy, coarse cake.
ButterAs a solid fat, butter is better suited for baking than any other fat product. Butter in particular adds flavour, with a melting point just below body temperature, which is why some cookies and baked goods tend to “melt in your mouth.” It also helps in leavening and adds moisture.
CornstarchThis ingredient has multiple purposes depending on the type of dish it’s being used in. Cornstarch is usually either a thickener or a binder, but can also be an anti-caking agent. It’s great to use in gluten-free cooking instead of flour to thicken sauces, custards, or cake fillings.
EggsEggs do a lot in baking, but most importantly they’re a leavening agent (adding volume), and are a binder, meaning they keep the finished product together. You can use the whole egg, for flavour, binding, thickening, or glazing, or you can use egg whites and egg yolks for separate things. Egg whites are a drying agent, and add moisture and stability. Egg yolks contribute to texture and flavour.
FlourFlour holds ingredients together in baking. When flour protein is combined with moisture and heat, it develops into gluten. Different types of flours have different levels of protein, which are suitable for various baked goods.
MilkThe protein in milk softens, contributes moisture, and adds colour and flavour to baked goods. It’s a double-whammy in terms of function, as it gives the dough or batter strength and structure, as well as adds tenderness, flavour and moisture.
SaltSalt does a couple different things in baking. For one, it helps preserve the colour and flavour of flour. In bread, it controls of the fermentation rate of yeast, and strengthens the gluten protein in dough. Though it seems salt is out of place in sweet recipes, if you skip it, your product will taste very bland, as it also enhances flavour.
Shortening
Shortening is just 100%, solid fat made from vegetable oils, almost exclusively used in baking. When you use shortening instead of butter in baking, you’ll get a softer and more tender, though taller and less flavourful, product.
SugarIn any given recipe, sugar is performing a number of functions you’re probably not aware of. For one, it adds texture, like keeping your baked foods soft and moist. It is also yet another leavener, though working in conjunction with fat, eggs, and liquid ingredients. Sugar sweetens by the sugar caramelizing in the recipe, and adds that “crunch” to the crusts of cakes and cookies.
