Good recipes for oatmeal streusel topping include uncooked old-fashioned or rolled oats, sugar and butter. Some variations include assorted spices. The spice choices are dependent on what the topping is paired with. Pumpkin pie spice is good with pumpkin muffins, and cinnamon is delicious with apple pie.
A basic oatmeal stresuel recipe calls for 1 cup of packed brown sugar, 1 cup old fashioned oats, 3/4 cup all purpose flour and 1/4 teaspoon salt combined together in a large bowl. Cut 1/2 cup cold butter into pieces and mix in with hands. Squeeze gently until the mixtures forms moist clumps, then cover and chill until needed.
For a Dutch apple pie topping, add in ground cinnamon with the dry ingredients. Start with 1/2 teaspoon, and add more to taste if desired. Adding 1 teaspoon lemon zest also brings delicious flavor to apple pie toppings. Cover the top of the pie if the streusel topping browns too quickly during baking.
A very simple streusel recipe that is perfect for pumpkin muffins includes 1/4 cup old fashioned oats, 1 tablespoon packed brown sugar, 1 tablespoon butter, melted and 1/8 teaspoon pumpkin pie spice. Combine all ingredients together in a small bowl, and sprinkle on top of muffin mix before baking.