Streusel coffee cake is a type of sweet cake with a crumb topping. Both the ingredients of the cake and the crumbly streusel can vary widely depending on recipe, personal taste, and available ingredients. Most streusel coffee cake recipes are very simple and can be whipped up in less than an hour, including cooking time.
A basic coffee cake recipe can easily be modified to make streusel coffee cake. Common ingredients in a simple coffee cake include all-purpose flour, white sugar, butter, and a leavening agent such as baking powder. Building on these primary ingredients, a coffee cake can then go in nearly any direction. It can be spiced up with cinnamon, nutmeg or cloves, or marbled with a ribbon of caramel or chocolate. Coffee cakes can also incorporate fresh fruit and some vegetables, such as blueberries, bananas, pumpkin, or zucchini.
The streusel component of the cake is usually quite simple to concoct. To make a good, crumbly topping, combine flour and oatmeal with butter and brown sugar, mixing until medium and small crumbs form. To add additional flavor, consider mixing in chopped nuts, such as walnuts, pecans, or almonds. Spices, like anise and allspice, can add a kick to flavor, and blend in nicely with many coffee cake recipes.
The key to a superior streusel coffee cake is adding the crumbly topping just before baking. If the streusel is added to the cake too early, it may sink into the batter. Once the cake is baking, the streusel will not be able to adhere to the drying batter, and will simply fall off. Adding the topping just before baking ensures that it will settle on top of the batter, forming an even top to the cake. If the topping is not browning according to preference, move the cake to the top level of the oven, or place in a broiler for one minute. When using a broiler, be sure to check the cake regularly, as burning can occur very quickly.
To add a level of fanciness to streusel coffee cake, consider adding a layer of fruit just underneath the streusel. Tart apples, nectarines, or firm peaches can make a wonderful fruit layer that will taste even more delicious when topped with crunchy streusel. When adding a fruit layer, be sure to make enough streusel to distribute evenly and thoroughly over the top of the fruit, as it will help keep the fruit from drying out in the oven.