Rhubarb and Cheddar Souffle Tart

Rhubarb is typically used as a sweet ingredient and made into jams and compote then combined with cream and sponge or some almond based crust. However it goes really well with a tasty bit of matured cheese or roast meats like a fatty piece of lamb. Rhubarb is naturally sour and works well with indulgent ingredients with a high fat content which is why I've used mature cheddar and egg yolks.
There is a bit of skill and patience involved in this recipe so make sure you read the method before you start. Also if you can get your hands on forced Yorkshire rhubarb you will get a better result in flavour, beware only in season round March and April.  

800g rhubarb
2 tablespoon extra virgin olive oil
800g desiree potatoes
8 eggs separated
60g plain flour
125g  butter
300ml whole milk
150g unpasteurized mature cheddar grated
1 banana shallot
1 tablespoon worcestershire sauce
Sea salt and cracked pepper season
Small handful rock
4 larger basil leaves
250ml balsamic vinegar

METHOD:
Place the potatoes unpeeled in a pot and cover with cold water and place over a medium heat, bring to a simmer and cook till tender about 40 minutes. Wash the the rhubarb and slice into 5cm pieces and lay out on a baking tray lined with parchment paper. Drizzle the olive oil over the rhubarb and lightly season with salt and pepper then place in oven set at 180oC for 25 minutes.
Peel and finely dice the shallot, place a sauce pan over medium heat and add the butter and shallots and cook till onion is translucent and tender. Add the flour and stir till the mixture starts to smell of shortbread then add the milk bit by bit while stirring to avoid lumps forming. Then add 100g of cheddar and worcestershire stir till cheese has melted, remove from heat and stir in the yolks till evenly combined, taste the sauce and add desired amount of salt and pepper and leave to stand.
When the potatoes are tender drain, hold potatoes in tea-towel and peel off the skin with a small sharp knife, then press the potatoes through a potato ricer or push through a fine sieve using the back of a spoon.
Using butter grease a fluted baking dish with removable base 30cm diameter and 3cm deep, then tap 2 tablespoons of plain flour round the tin coating the butter.
Place the egg whites in a large mixing bowl and using a electric beater whisk the eggs till stiff peeks form. Fold half the cheese sauce in with the potatoes then gently fold 1/3 of the egg whites in with the cheese sauce/mash potato combo. Fold in the rest of the cheese sauce then fold in another 3rd of egg whites till just incorporated then repeat with remaining 3rd of whites.
Pour the mixture into into the baking dish and evenly distribute the rhubarb over the top of the tart then sprinkle the remaining cheddar on top.
Place a tray of warm water at the bottom of the oven and put the tart on the center shelf above the water and bake at 160oC for 40 minutes.
Place the balsamic vinegar in a small sauce pan and bring to a steady simmer over medium heat and cook till reduced to a sticky syrup.
Once cooked leave to cool for 15 minutes before removing the base from the outer dish. Cut tart into 8 piece's and garnish with rock and finely slice basil leaves then drizzle the balsamic reduction over the tart and now its ready to serve.