Give me a good tarte aux pommes over apple crumble any day.

Having said that, I do still have an old man’s love for the classic crumble, thanks Grandma…and Dad!

So here’s my solution. An apple crumble, flipped literally on it’s head. A crumble base, filled with a baked custard and crowned with thin slices of spiced apple.

Click below for the full recipe.

This made enough for a tart baked in a 12cm/6″ cake tin

Prepare the crumble base

Lin a spring bottomed cake tin with baking paper [0:25-0:50 in the video ].

Mix the flour, sugar, butter and oats to a lumpy consistency ( ~ 2 mins)

This can be done with a mixing spoon, but I find your hands make a much easier job of it.

100g plain flour
100g oats
75g butter
100g light brown sugar

Pour the crumble mix into lined cake tin and work it into the form of a tart case [1:08-1:24 in the video ]

Again, use your hands. First press the crumble mix into the tin’s sides to form the tart walls, then press down to form the base (don’t forget the corners). It’s also a good idea to prick the the base and walls with a fork, which will allow steam to escape during the bake, minimizing deformation.

Transfer the crumble tart case the oven and bake at 180°C (160°C fan). (30-40 mins)

The tart will bubble and deform, don’t panic. Continue to prick the tart case midway through and straight after the bake allow steam to escape.

Remove it from the oven pressing any rough patches back into shape using a glass or other smooth sided object. [1:33-1:48 in the video ]

Leave the tart to cool in the tin ( ~ 15 – 30 mins)

As the tart cools, you can prepare the custard filling.

Preparing the custard

This may make too much cusdtard, but better to have too much than too little. No such thing as too much custard anyway is there…

OK fine, if you do want to adapt change the amounts, I use a 1:2:6, sugar, butter, dairy ratio. This is weight based, with the average yolk being 17-18g meaning you’ll need about 8g of sugar and 54g of liquid per yolk.

Seperate your eggs, keeping the yolks.

5 eggs

Whisk the sugar and vanill into the yolks.

No need to whisk vigorously here, all we want is to evenly disperse ingredients, not aerate.

5 yolks
42g caster sugar
1 tbsp vanilla extract.

Warm your dairy until close to boiling ( 5 mins stovetop / 1 mins microwave)

The recipe originally asked to use cream, however, if like me, you have none, you can make cream by combining 7 parts melted butter to 9 parts warm milk. If you mix the two together with a hand blender as you would a dressing, the butterfat is dispersed and suspended through the milk, forming an emulsion of butterfat, aka double cream.

270ml double cream

170ml milk
100g butter

Whisk the warmed cream into the yolk mixture.

Here, you always add hot to cold. Remember, you’re warming the eggs with the milk, not cooling the milk with your delicate eggs.

Pour the warm custard into the cooled crumble tart case.

It’s a good idea to have your cake tin and tart on another baking tray here. This way, you catch any butter or custard leakages, and prevent the base from overcooking (use the lightest coloured baking tray you have)

Transfer the tin back to the oven, turning it down to 140°C (120°C fan). (30-40 mins)

Thus custar goes into the oven at around 60°C, so it only needs to heat up another 15-20°C to set. This still takes time so don’t get impatient. Playing with the oven temperatures to speed thing up will only lead to an unevenly baked, scrambled egg like custard.

The tart will be ready when the custard reaches about 75-80°C.

You can carry out this step as the custard bakes

Preparing the apples

Prepare a salt water solution.

You’ll be immersing the apples in this as you cut them, so have it to hand.

250ml of water
1 tsp salt

Cut the apples into thing slices, placing them in the salt water as you go [3:28-3:34 in the video]

3 apples
salt water solution

Let the apple slices soak (10 munud)

This is intended to deactivate the enzymes in apples responsible for oxidation and browning. The idea is that the salt dries out the cells at the apple’s surface via osmosis, which means that enzymes in these cells are unable to move and function effectively.

After 10 minutes, drain the apples, rinsing them with cold water to wash the salt off.

You should then be able leave the apples as they are for at least a few hours before signs of browning appear, more than enough time for the custard to finish baking and for the tart to be topped.

Once the custard is ready and out of the oven.

Lay the apple slices in a flat spiral on top of the set custard. Finish with some cinnamon and nutmeg [3:50-4:02 in the video ]

pinch cinnamon
pinch nutmeg

Bake under the grill on about 150°C (15 min)

I chose the grill as the direct heat would rapidly cook the apples on top, without further baking the delicate custard underneath. You can protect the exposed crumble edges with some strips of foil.

Chill the tart in the fridge, and enjoy!

More stuff

A pretty full on experiment, but the results speak for themselves! For more on what’s going on with this crumble pie, head over to the Lab and take a look at some of our articles, such as Examining Eggs and Bringing Salting Back (all to come!).