Slice the apple into bite sized pieces, and place in a small microwaveable baking dish or bowl.
Stir ¼ teaspoon cinnamon and ½ teaspoon brown sugar into the apples. Squeeze in about ¼ of a lemon and stir together.
In a small bowl, stir together the oats, nuts, and the remaining ¼ teaspoon teaspoon of cinnamon and ½ teaspoon brown sugar.
Using a fork or you fingers stir in the butter and try to get most of the oat/nut mixture coated with butter. It should feel like wet sand. Sprinkle crumb topping over apples.
Microwave on high for 2-3 minutes until apples are softened. Let cool for a minute and enjoy!
Notes
*Great topped with a scoop of ice cream or vanilla yogurt.*Use old-fashioned or quick oats, not flavored or steel cut.*Any nuts or seeds will be delicious or omit if desired.*Recipe was tested using a 7x5 shallow baking dish.*When testing, apples were ready after 2:35 minutes.