Peel and thinly slice apple. Toss apple slices with 1 Tbsp brown sugar, ½ Tbsp quick oats, ½ Tbsp flour, ⅛ tsp cinnamon and 1 tsp lemon juice. Place in a microwaveable dish (ramekin, bowl, etc.)
Using a fork, combine the remaining ingredients with butter for the crumb topping. (1 Tbsp brown sugar, 1½ Tbsp quick oats, 1 Tbsp flour, ⅛ tsp cinnamon, and 1 Tbsp of butter.) Sprinkle over apples.
Microwave for 60 to 90 seconds until apples are tender. Serve plain or with a small scoop of vanilla bean ice cream.