This is my autumnal take on a classic lemon meringue pie. I've been inspired by my friend, Clare McQuillan, who is a talented forager and cook. Clare made a number of delicious meringue pies over the last year or so using wild ingredients, a couple of which I have been lucky enough to taste. Making a curd (which is basically the filling in a meringue pie) is a great way to use wild and trickier to process ingredients as you can just boil them up whole (without a lot of peeling, chopping, deseeding) and then strain them through a muslin to get the juice for the curd.  This year the little crab apple tree in my Mum's garden was laden down with glossy, bright red crab apples, so after making as much crab apple jelly as any one family can reasonably eat I was inclined to do something a bit more decadent and hence this Toffee Apple Meringue pie!

The combination of sharp apple curd and salted caramel gives this pie a Halloween/Bonfire season feel - hence the Toffee Apple name. Admittedly, this is not a quick or easy recipe, there are lots of elements and quite a few processes too, so it is a bit of a labour of love! Totally worth it of course!

However, there are a couple of cheats if you want something a bit less involved. For the pastry I've used a brilliant pâte sablée recipe from Liz Prueitt of Tartine Bakery in San Francisco. I love this recipe as the pastry is very forgiving and you don't need to use baking beans when blind baking it. The recipe makes enough pastry for two tarts, but the uncooked pastry freezes well or keeps in the fridge for up to 4 days. But you could definitely use your own traditional shortcrust recipe (something you are comfortable with making) or even buy the pastry - though do try to go for an all butter shortcrust. For the salted caramel I've used this recipe on the BBC Good Food website but I've also used some of a jar of ready made caramel sauce, this one by Cloudberry is really delicious.

Serves 10

For the pastry:

• 125g butter (at room temperature)

• 100g caster sugar

• A pinch of salt

• 1 large egg (plus a bit extra to egg wash the tart case)

• 250g plain flour

  
  This makes enough pastry for two tarts, it’s tricky to make a smaller amount in the mixer. The uncooked pastry freezes well.

For the filling:

• 750g crab apples

• 750ml water

• 20g cornflour

• 100g caster sugar

• 75g butter

• 3 egg yolks and 1 whole egg (gently whisked together)

• 50g - 75g salted caramel sauce

For the meringue:

• 4 egg whites

• 225g caster sugar

• 2 teaspoons cornflour

Start with the crab apple filling. Wash the crab apples well and put them in a saucepan. If they are large cut them into halves or quarters. Cover them with 750ml water. Turn on the heat to medium and bring to the boil. Boil gently for about 30 minutes until the crab apples are soft and have burst. Ladle the boiled crab apples into a sieve or colander, that you have lined with piece of muslin or a clean tea towel, over a bowl. Gather up the edges of the muslin and secure with a string and hang up from a cupboard handle or similar allowing the liquid to drip into the bowl. Allow to drip for 4 hours or overnight.

Next make the pastry. For the pastry put the butter, sugar and salt into a stand mixer with the paddle attachment and mix on a medium speed until smooth. If you don’t have a stand mixer you can do this by hand. Once smooth, mix in the egg. Scrape down all the sides with a spatula and then add all the flour at once and mix on a low speed until just combined. Turn out the dough onto a floured surface, divide it in half and shape each half into a round disk about 1.5cm thick. Chill in the fridge for at least two hours.

Take one disc of pastry out of the fridge, place on a lightly floured surface, and roll it out until it is about 3mm thick (the thickness of a pound coin). Use it to line your tart tin. I used a 23cm (9inch) wide tin that was 4cm deep, you could go slightly larger or smaller depending on what you have, but the proportions of the tart will change slightly. Trim the overhanging pastry to just about the top of the tart tin, I always find it shrinks slightly no matter how careful I am, so this gives you some leeway. Chill the pastry for 30 minutes.

Preheat the oven to 170°C. Prick the base of the tart several times with a fork. This will stop it bubbling up. There is no need to use baking beans with this pastry. Put it in the oven and bake for 10 minutes. Remove from the oven and brush the egg wash all over the inside of the tart shell. Put is back in the oven and bake for a further 5 minutes. Remove from the oven an allow to cool, keeping it in the tart tin.

Now, back to the filling. Measure out 325ml of the apple juice into a saucepan and add the sugar and cornflour. Turn the heat onto medium and bring to a simmer stirring the whole time, the liquid will thicken. Once it is simmering take it off the heat. Stir in the butter until is has completely melted and then stir in the eggs. Put back onto a medium heat and stir continuously until the mixture bubbles and is very thick, it will sort of plop of the spoon.

Warm the salted caramel a little (in a pan or the microwave) just until it is spreadable. Spread it in a very thin layer over the bottom of the tart case. Put the tart case in the freezer for 10 minutes. Pour the warm crab apple curd over the top and spread it out until level. Put the filled tart case back in the fridge until completely cold.

Preheat the oven to 170°C. Whisk the egg whites in a stand mixer or with an electric whisk until stiff but not grainy. Add the sugar a tablespoon at a time, whisking between each spoonful, until thick and glossy. Add the cornflour and whisk it in.

Remove the filled tart from the fridge. Dollop the whisked meringue all over the top of the tart spreading it out until it touches the edge of the tart case. Use a spoon to swirl the top of the meringue into a pleasing pattern.

Put into the oven a bake for 15-25 minutes until the top of the meringue is crisp and golden. Check it after 15 minutes, but it might take longer.

Take the pie out of the oven and allow to cool completely before serving.