Apple streusel muffins are small cakes that contain chunks of apple and are covered with a crumbly, sugary topping. Like other muffins, they are not thick and cake-like but are coarser and more bread-like. The apple chunks lend more moisture to the mix, though, so the muffins can be quite dense. Apple streusel muffins can be of various sizes.
Streusel itself is the crumb topping. Typical ingredients are flour; butter; spices, such as cinnamon and nutmeg; and sugar, which can be either white or brown. Streusel toppings go on before the muffins are baked so that the crumbs brown well and become a bit crunchy. The look of streusel ranges from a layer of finely ground crumbs to lumps crowding around the top of the muffin. Sometimes the streusel includes a white glaze made of milk and powdered sugar drizzled over the crumbs after the muffin is done baking.
Although there are ingredients that show up in apple streusel muffin recipes in general — such as apples, sugar, butter and some type of flour — there is a lot of wiggle room. The baker can add nuts, can vary the amount of spices or delete one if desired or can modify the ingredients to lessen the amount of fat. Different flours can make the muffins gluten-free, if needed, and other grains, such as flaxseed or oatmeal, can add fiber.
The level of sugar in apple streusel muffins means they are suitable as a sweet dessert, and they are especially popular as breakfast food. As versatile as these muffins are, though, there is a caveat. All that sugar and butter will add calories and extra fat, and anyone eating them must adjust his or her diet so that it remains balanced.
Fruit muffins seem like they would be a healthier choice because of the implied addition of fiber and vitamins, but the heat from cooking can destroy a lot of heat-sensitive vitamins, such as vitamin C. The fruit cooks down and doesn’t take up all that much space, so the muffin is still mostly sugar, fat and flour, rather than being a low-calorie fruit dessert with a little cake added. Using apple chunks can provide bakers with a lower-calorie add-in, compared with something such as chocolate chips, but overall, people who are making or eating apple streusel muffins must still watch the overall amounts of sugar, fat and calories in the particular recipes that they use.