Apple Crumble Bars

Bahan-bahan (9 porsi)

• 125 g / 1 stick unsalted butter (, melted)
• 2 cups (300g) flour (, plain/all purpose)
• 1/2 cup (100g) white sugar
• 1/2 tsp baking powder
• Pinch of salt
• 1 egg
• 1/3 cup (30g) rolled oats (Note 1)
• 3 - 4 large granny smith apples (, cut into 0.7cm / 1/3" dice(~4 cups))
• 1/4 cup (35g) plain flour ((all purpose flour))
• 1/4 cup (50g) white sugar
• 1/2 tsp cinnamon
• 1/4 tsp nutmeg
• Salted caramel sauce
• Ice cream!