Hasselback Apples with Nutty Streusel Topping

I don't quite know how I came about baking this because really, out of everything, it's rather an Autumnal recipe... with the sweet scent of cinnamon and nutmeg wafting out of the oven, it completely juxtaposes to this lovely Summery weather we've been having in the UK recently. 
I suppose I was just in the mood for something warming and comforting, which is exactly what this sweet little pudding provides! It's like apple crumble in a way - with the streusel topping giving richness and that all important crunch from the demerara sugar, walnuts and flaked almonds. 

I've only discovered what hasselback potatoes are just lately... (sorry, I'm a slow learner!) But, when I realised that you could literally do this with anything you can slice, soooo  i.e. most fruit and vegetables, I just had to give this a go! AND make it a dessert one of course!!

I feel I might have put you off the fact it's quite an Autumn/Winter' ish recipe and it's Spring (well at least here in the UK it is...) but please do make this all year round. It's perfect for any time. What the heck, go even have it for breakfast!  (I've just thought about how deliciously naughty but good this would be for breakfast, mmmm) baked breakfast apples exists as a thing so why not have streusel too?! 

I should point out that this recipe doesn't make a lot. Serving 2 ( 1⁄2 an apple each) or one generous portion - if you're really up for it. But it can easily be doubled and most of the ingredients are listed in measurements of tablespoons etc. so it's super quick and easy to do. 
Note: I would recommend serving this with a scoop of good quality vanilla ice cream or custard. 

Hasselback  Apples  with  Nutty  Streusel  Topping 

Makes 1 large portion or 2 smaller ones

Ingredients:

1 dessert apple 1 tbsp melted butter 1 tbsp brown sugar (light or dark is fine) 1⁄2 tsp cinnamon 1⁄2 tsp nutmeg 1⁄2 tsp vanilla extract
For the streusel topping: 30g cold butter  4 tbsp plain flour 1 tbsp demerara sugar  1 tbsp roughly chopped walnuts 1 tbsp flaked almonds

Method

Preheat the oven to 200°C/ 400°F/ gas 6. Peel and slice the apple in half. Remove the stalk and use a melon baller to remove the core and pips. Use a knife to make lots of slits in both apple halves, making sure you cut down far enough but not all the way through to the other side. Place the apple halves into a small baking dish, flat side facing down. 
Mix the melted butter, sugar, cinnamon, nutmeg and vanilla in a small bowl, then brush all over the apple, letting it flood down to the bottom of the dish. Bake the apple in the oven for 20 minutes. Meanwhile to make the streusel topping, cut the butter into cubes and rub into the flour. Stir in the sugar and nuts. 
Once the apple have baked for 20 minutes, scatter over the streusel mixture and bake again for 15 minutes until the streusel is lightly golden. Serve straight away.