While the oatmeal is still cooking, mix the apples, brown sugar, cinnamon, lemon juice, and salt in a bowl and set aside for about 10 minutes while the oats finish cooking. While the fruit mixture rests, it will give off more liquid which will act almost as a fruity, lemony syrup for the oats.
1 apple, 1 to 2 tbsp brown sugar, ½ tsp cinnamon, squeeze of lemon juice, pinch salt