Place the diced apple in a microwave-safe bowl, (one large bowl or mug or two smaller ones for two servings). Add lemon juice, sugar, cinnamon, and water, stirring to coat.
1 medium apple, 1 tsp lemon juice, 1 & 1/2 tbsp brown sugar, 1/2 tsp cinnamon, a pinch nutmeg, 1 tsp cornstarch
If using two small containers, mix the diced apples with the sugar, cornstarch, spices, and lemon juice in a bowl then divide into the two ramekins
Microwave for 2 minute on high heat to soften the apples.
In a separate bowl, mix the oats, flour, brown sugar, salt, cinnamon, pecans, and melted butter until combined.
2 tbsp rolled oats, 2 tbsp flour, 2 tbsp brown sugar, 5 pecan halves, 1/2 tsp cinnamon, pinch of salt, 2 tbsp butter or coconut oil
Spoon the oat topping over the apples in an even layer. Microwave on high for 2 minute, or until you can see the apples being bubbly and the topping is a little crisp.
Let cool for a 2-3 minutes, then enjoy as is or with a scoop of ice cream on top!