Preheat the oven to 200C/400F and spray a 12 hole muffin tin with cooking spray. First up we're going to make the apple pie filling, so it has some time to sit. Peel, core and cut the apples into small chunks. Place them in a medium sized bowl, then add the light brown sugar, cinnamon, nutmeg, cornflour and vanilla extract. Stir until all the apples are coated in the flour mix and leave to one side.
Make the topping: Place the flour, sugar and butter into a small/medium bowl and rub between your fingers until the mixture starts to clump up and become larger and smaller crumbles. You can use a pastry cutter, but for crumble toppings, I find hands better as the heat from your hands works better on the butter to create those larger crumbles.
Leave the crumble topping to one side and make the pastry: Place the butter, flour, sugar and egg into your food processor and pulse until you have a coarse breadcrumb texture. Then add ice cold water, 1tbsp at a time and pulse for at least 30 seconds between each addition. When the mixture balls up and becomes one big lump you're done.
Alternatively, you can place all the pastry ingredients in a large bowl and use a pastry cutter to cut the butter into the flour. Once you have a coarse breadcrumb texture, add the water 1tbsp at a time, bringing the mixture together with your hands or a spoon until a dough forms.
Flour your work surface and tip the pastry out. Flour the top of the dough and then roll out until the pastry is around 2-3mm thick. Use a 9-10cm round cutter to cut 12 rounds out of the pastry. You may have to cut a few, then re roll the pastry to get the rest.
Gently lift a pastry round over to your sprayed muffin tin and then press the centre down into the hole, while easing the sides in so you don't get pastry folds. Be very gentle so as not to tear the pastry. The pastry should come 3/4 of the way up the sides of the hole in your tin.
Divide the apple mixture between the 12 holes. Fill each pastry round level. You want a little bit of the sauce that's been created by the mixture sitting for a while in each one. But be careful not to flood the pastry.
Once each mini pie is filled with the apple mixture, spoon 1tsp of Toffee Sauce onto the top of the apples. You don't have to spread it much as this will happen while baking, just drop it into the centre of each mini pie and smooth the top over so it doesn't stand too tall.
Now for the final layer! Sprinkle each mini pie with some of the crumble mixture. You'll have more than enough, so you can add as much as you want. If you want to entirely cover the top, go for it. I prefer to have bits of apple and sauce peek through. With the extra crumble mixture, I crumble it onto a small baking tray and bake it for 10-15 mins at 200C/400F, until golden, to create a crunchy snack!
Place your mini pies into the oven for 15-20 minutes, until the top is golden and the sauce is bubbling. If you poke a piece of apple with a knife, it should be soft. Leave to cool in the pan for about 10 minutes (just so the toffee sauce isn't molten) and then use a sharp knife to gently ease the mini pies out. The pastry itself shouldn't be stuck, but if the toffee sauce has leaked then you'll just have to cut through that bit. Place the pies on a wire rack to cool completely.
You can serve these pies with vanilla ice cream and more toffee sauce, dusted with powdered sugar, hot, cold. They're delicious any way!
Mini Toffee Apple Crumble Pies will keep at room temperature, in an airtight container, for 5 days.