Tarte tatin is one of my most favourite dishes. I love mine with some spice so below you will find a variation that I think it really enhances it.

Ingredients
4 eating apples 
Juice of 1 lemon
110g caster sugar
40g butter
Pinch of flaky salt
1 packet or ready rolled puff pastry
1 egg yolk 
1 tsp water

Equipment needed 
23cm frying pan that will work both on your hob and in your oven 

Method
Start with your pastry. Unroll your pastry and put your pan on top of your pastry. Cut around the pan on to your puff pastry, a cm bigger than the pan as you are going to tuck it in.  If the pastry is not quite big enough, you can cut a little patch off of the scraps and press to join it together to make it a circle. Put the pastry back into the fridge. 

Peel the apples and cut into quarters, removing the cores.  Put the quarters in a non-metallic bowl with the lemon juice and 1 tbsp of the sugar. 

Put the butter and sugar pastry into the pan on a medium high heat and cook until the butter melts, tilting the from time to time, circling the butter into the sugar.  Reduce the heat to medium and cook shaking the pan occasionally until a beautiful toffee colour caramel forms. 

Place the apple quarters into your frying pan, rounded side down, arranging them around pan, jiggling and pushing until they are all in snugly. Pour over 2 spoonfuls of the lemon juice left in the bowl. Cook the apples over medium heat for about 5-10 minutes until caramel is a deep toffee colour and bubbling up in the pan. Shake occasionally to prevent burnt spots.  Leave to cool for a minimum of 15 minutes.

Meanwhile, mix your egg with the water, unroll your pastry and put the egg wash over the pastry. Put back into the fridge.

When you are ready to cook preheat the oven to 200c. Take your chilled puff pastry and put it over the top of your apples and tuck the pastry down the sides of the pan.  Egg wash your pastry one more time. Cook for 25-30 minutes until the pastry is puffed and a deep golden. 

When you take the pan out of the oven, immediately wrap the handle with a tea towel as this will prevent you grabbing the handle and burning yourself.

To serve this dish properly you should turn out.  To do this you need to leave it to cool for 5 minutes then get a butter knife and run around the edge to loosen any stuck pastry.  Put your hand firmly on the top of the pastry and slowly start to turn clockwise, you don't need to move this too much, just enough to know it is not stuck anywhere.  Get a plate and put on the top of the pan and hold it firmly.  Holding the pan handle with a tea towel, quickly without overthinking it, turn the pan upside down so the tart is on the plate, apple side up.