Begin by washing and chopping one apple into small, even pieces, ensuring uniform cooking. In a microwave-safe mug, combine chopped apples, cinnamon, and maple syrup.

For a softer texture, microwave the apple mixture for 30-45 seconds on high.

In a separate bowl, combine rolled oats, almond flour, protein powder, salt, and cinnamon. Gradually add water or almond milk until the mixture is just moistened.

Spoon the crumble mixture over the softened apples in the mug, spreading it evenly.

Place the mug in the microwave and cook on high for 1 to 2 minutes, watching carefully.

Remove the mug and let it rest for 1 minute. Serve warm, optionally topped with Greek yogurt or nut butter.