Making moist chocolate muffins can be difficult, especially if cocoa powder is used, because it tends to cause the muffins to dry out a little quicker than normal. Some of the most classic tips for creating moist chocolate muffins deal with adding ingredients — such as shredded zucchini, carrots or chopped dried fruits — that retain moisture and release it slowly into the batter as it cooks. Another idea is to boost the batter with moist thickeners such as yogurt, buttermilk or sour cream, all of which have the added benefit of being acidic so they interact favorably with the cocoa in the muffins. The type of fat that is used also can help to make moist chocolate muffins, although using something like lard can create a slightly different texture in the final muffin. Avoiding dry muffins largely relies on ensuring that the muffins cook through just enough and removing them from the heat before they start to dry out and become hard, which can ruin even the moistest batter.
One way to keep the inside of a chocolate muffin moist is to add an ingredient that is somewhat wet and will slowly release moisture into the batter while it bakes, usually in the form of steam. Zucchini is a popular choice, because it is mostly water and can be grated into small pieces that will almost completely disappear into the muffin without adding a strong taste. Dried fruits such as apricots and raisins can serve the same purpose. For a very moist muffin with a sweet, lightly fruity taste, mashed bananas can be added.
A popular way to make moist chocolate muffins is to add a thick liquid as a substitute for some of the fat or eggs in the recipe. This includes plain or flavored yogurt, buttermilk, sour cream for a tart taste, or applesauce. The moisture might make the muffins a little heavier, depending on the ingredients, but the texture should be very rich.
The type and amount of fat used may make moist chocolate muffins but might not help their nutritional value. Using extra egg yolks or extra butter can make a softer crumb in the muffin, although care has to be taken because too much fat will prevent the batter from adhering to itself while cooking and might actually weep out of the muffin. Less popular fats, such as lard or suet, can be used in muffins to help them remain moist longer, although they also might make the texture chewier than expected or desired.