• Preheat oven to 300 F (150C). Grease with butter an 8-inch (20cm) square baking pan. Line with parchment paper.

Prepare the crust.

• In a large bowl add the butter, sugar, vanilla and salt. Mix until creamy.
• Incorporate the flour, ground almonds and cinnamon.
• Press the mixture evenly onto the bottom of the prepared baking pan.
• Bake for about 15-18 minutes until lightly golden brown. Set aside and let cool slightly.
• Turn on the oven to 350 (180C).

Prepare the crumble topping.

• In a large bowl combine rolled oats, flour, ground almonds, brown sugar and cinnamon.
• Add the melted butter and mix until crumbs are formed. Set aside.

Prepare the apple filling.

• Peel and core the apples and cut into ¼-inch (6mm) slices.
• In a medium bowl toss the apple slices with sugar, flour, cinnamon and nutmeg.
• Spread the tossed apples over the crust.
• Sprinkle the crumble topping over the apples.
• Bake for 30–35 minutes or until the crumble is lightly browned and the apples are tender.
• Let cool at room temperature then chill for 2 hours.
• Cut into bars and serve with a drizzle of salted caramel sauce.