BUTTER: Melt the butter in the microwave and set it aside to cool a bit. (Do not use hot butter-- it will melt the sugar and result in a greasy streusel.)
COMBINE: In a large bowl, combine the flour, brown sugar, cinnamon, and salt. Use a spatula to scrape every bit of cooled melted butter into the bowl.
MIX: Stir until ingredients are well combined.
KNEAD: If needed, use your fingers to knead the mixture together until it forms coarse crumbs. The streusel is now ready to be used as a topping for pies, cakes, muffins, or any other baked goods. (Sprinkle the streusel on top of the batters/pies/crisps before baking).
Notes
Note 1: Brown sugar: Use fresh, soft brown sugar to ensure that the streusel doesn't end up dry with chunks of hardened sugar!Nutrition information is based on 12 servings--what you'd use for muffins, pies, etc.