In a medium bowl, combine flour, sugar, cinnamon, and salt. Using a pastry blender or fork, cut in the butter until fine crumbs form.
Using hands, squeeze together most of the mixture to form large clumps. The topping can be frozen in an airtight container for up to 6 months.
This is a wonderful topping for muffins and coffee cakes. And you can freeze what is left over to use on another recipe.