This streusel topping (or crumb topping, as it's sometimes called) will really spruce up your homemade muffins, pies, coffee cakes, and quick bread. It takes only seconds in a food processor, or you can just mix it up in a bowl using a fork. Sprinkle it over your muffins or pie right before baking for a traditional, sweet, crispy, crumbly topping. To always have the streusel on hand, you can mix up all of the ingredients except the butter and store in the pantry. Then when the time comes, simply pour into a food processor, add the butter, and mix until crumbs form.