Melt the sugar in a large frying pan over medium heat until it turns a golden color.
Combine the apples with the sugar for a few minutes
Add the lemon zest and cinnamon stirring everything together.
Add the butter and continue to stir for a few more minutes.
Cover the pan with the lid and simmer without stirring, for 5 minutes until the apples have softened but retained their shape.
Stir in the blackberries and continue to simmer for another 5-10 minutes until all the fruit is tender.
Set aside to cool.
For the crumble topping:
Rub and squeeze gently together the flour and butter in a large bowl using your fingertips. You don't need to rub until you get fine breadcrumbs so that we achieve a courser texture.
Add the sugar and oats making sure you mix everything well together.
Mix the cinnamon and nutmeg.
Set aside until needed.
For assembling the apple and blackberry crumble:
Preheat the oven to 200C/180C Fan
Transfer the cooked hot apples in a casserole
Spoon the blackberries evenly across the apples and completely
Cover evenly the fruit with the crumble mix.
Bake the tart at 200C/180C Fan for 30 minutes, or until the crumble turns crisp and golden-brown.
Allow it to stand for a few minutes.
Serve the crumble warm in slices, with custard or cream on the side.
Notes
Using fresh lemon zest and juice: Adding lemon zest and a squeeze of fresh lemon juice to the fruit filling brings a bright and tangy flavor that complements the sweetness of the apples and blackberries.
Adjust sweetness: Taste your fruit mixture before adding sugar and adjust the amount based on the natural sweetness of the fruits. You can also substitute some or all of the sugar with a natural sweetener like honey or maple syrup.
Combination of oats and flour in the topping: For added texture and nuttiness, we mix rolled oats with the flour in the crumble topping. This will give your crumble a wholesome and satisfying bite.
Adding spices: We enhance the flavor profile by adding spices such as cinnamon, nutmeg, or ginger into the fruit mixture. These warm spices will beautifully complement the fruit flavors.
Mixed Berry Crumble: Instead of using only blackberries, try using a mix of different berries like raspberries, blueberries, and strawberries. This variation adds a burst of vibrant colors and a medley of berry flavors to the crumble.
Gluten-Free Crumble: Substitute the all-purpose flour in the topping with a gluten-free flour blend or almond flour for a gluten-free version of this dessert. Ensure that the oats you use are certified gluten-free as well.
Nutty Crumble: Add chopped nuts like almonds, walnuts, or pecans to the crumble topping for an extra layer of crunch and nuttiness. Sprinkle them on top before baking for a delightful texture.
Coconut Twist: Mix shredded coconut into the crumble topping for a tropical twist. The coconut adds a subtle sweetness and a hint of exotic flavor to the dessert.