Poached Onion & Salty Cheese Tart

• 250g plain flour
• 125g butter
• pinch of salt
• 1 medium egg yolk
• 25-50ml cold milk

• 2 large onions, sliced
• knob of butter
• sea salt and ground black pepper
• 50 g good, strong blue cheese, crumbled
• 50 g feta cheese, crumbled
• 2 medium eggs
• 2 medium egg yolks
• 350ml double cream

1. Bring the flour, salt and butter to a breadcrumb consistency by pulsing in a food processor. If you don’t have one, break up the butter into small bits and stir mixture with a wooden spoon until you reach the breadcrumb stage.
2. Mix in the egg yolk and then add the milk in a gradual stream until the dough begins to form together. Place on a surface and knead a few times – now wrap it in cling film/saran wrap and refrigerate for half an hour.

1. Use this time to prepare the filling, but first turn on the oven to 170 C°/338 F°. Put the onions, butter and some salt & pepper into a pot with 100 ml of water. Bring this all to a gentle simmer and cover it, stirring occasionally. Cook for about 10 minutes or until the onions are cooked but still with a slight bite to them. Now drain this mixture very well but keep the onion liquor that you drained. Set filling aside.
2. When the onion liquor has cooled, beat it together with the cream, eggs and egg yolks until smooth and add seasoning to desired taste, keeping in mind the saltiness of the cheese. Set this aside.
3. Remove the chilled pastry from the fridge and roll on a floured surface until fairly thin. Use this to line a loose-based 25cm tart tin. (It’s ok if you don’t have this specific tin, I’ve made it work with tins that weren’t loose-based or 25cm. It is important that the tin isn’t too deep though as this will highly increase the cooking time.)
4. Line the tart with greaseproof paper and then baking beans and bake blind for 20 minutes (I’ve used lots of salt in lieu of baking beans before). Remove from oven, take away the paper and beans and prick the base all over with a fork. Now return the tart to the oven for 5 more minutes until it becomes dry and slightly coloured. After you’ve removed the tart turn the oven up to 180 C°/356 F° and trim the excess from the edges of the tart, if you have any.
5. Spread all of the onions on the base of the tart and cover with the crumbled cheeses. Submerge all of this with the onion liquor mixture and place in the oven for around 30 minutes. You’ll know the tart is cooked when shaking it makes it wobble slightly and the liquid is set. Allow to cool slightly before serving.

Use leeks instead of onions, as in the original recipe from River Cottage. Save the egg whites in an airtight container and use them to make a healthy omelet!