Preheat oven to 200 degree C. Line muffin pan with liners and set aside.
Start by making crumbles. Take flour in a bowl, add in salt and mix well.
Add butter and rub it into the flour.
Add in sugar, walnuts and oats and mix well. Set aside in fridge till needed.
Now make apple crumble muffins batter. Take flour, baking powder and cinnamon in a bowl and mix well.
Add in chopped apples and mix well.
In a separate bowl mix milk, brown sugar, oil and vanilla and mix well.
Pour it into the flour mix and fold gently.
Scoop this into the mould and top with crumbles.
Bake for 20 to 30 mins.,
Remove and serve warm.
Video
Notes
1)You can make the crumble topping ahead and store in a ziploc bag in fridge for upto a week. You can store in freezer for more than a month. 2)Muffins can be baked and stored in freezer. Reheat in microwave when serving.