Preheat the oven to 190 degree Celsius.
Put the apple slices and 2 tbsp sugar in a bowl and lightly toss it together. Next, put this mixture into a 9x13-inch round baking dish or 6 individual dishes.
Take a bowl, add in the flour with the caster sugar and a pinch of salt, then add the butter and rub it with your fingertips so that the mixture looks like breadcrumbs.
Pour this crumb mixture on top of the apples and make sure to even it out. You can do this procedure with the back of the fork to make sure the crumble is crisp and held together.
Lastly, sprinkle the oats and brown sugar on top.
Bake this for for 35-40 minutes or until the top part turns golden in colour.
Serve warm with a garnish of the skinned almonds on top.