In a medium bowl, combine the dry ingredients and stir together to distribute everything evenly.

Melt the butter, then pour it over the dry ingredients, drizzling it over the entire surface of the flour mixture.

With a fork, gently fluff the mixture and fold the butter into the flour and sugar. Be sure not to break up too many of the clumps that form, but cut any overly large clumps in half. Keep mixing until all the dry ingredients have been incorporated into the butter.

When your batter has been poured into the baking dish, scoop the streusel topping out with a tablespoon and sprinkle it evenly over the surface of your cakes, muffins, or loaves. This recipe makes enough topping to generously cover two loaf cakes or about 12 muffins.

Bake your recipe as you normally would, testing with a toothpick when the baking time is up, and increasing baking time by about five to ten minutes if necessary. Additional baking time may not be required with the inclusion of the topping, but you may need to bake just a bit longer if your baked goods have a lot of extra streusel.