The key is to get a good, dark rich chestnut brown colour on your onions, this can take anywhere up to 2 hours. Yes really! If you haven’t got that long, don’t do this dish. At some stage during the initial frying of onions, they will ooze a lot of water (in the same way mushrooms do) and turn a bland colour of nothingness. Don’t attempt to drain them, just be patient. You’ll also need to stir fairly regularly and don’t be frightened to scrape all the brown stuff off the bottom of the pan as they caramelise…just as long as it is brown stuff and not black stuff.
2Kg red onions, thinly sliced. Neatness and uniformity are not important.
2 average cloves of garlic, crushed
150g salted butter
A generous bunch of thyme, tied together with string. (Why? Because otherwise you’ll spend days searching through the oniony haystack for hundreds of thyme stalk needles: much easier to find one piece of string)
2 bay leaves
½ - 1 teaspoon of salt
½ teaspoon of black pepper (that’s about 20 ’satisfactory’ turns with mine)
3 whole eggs + 2 yolks
250ml of double cream
Here we go:
First, blind bake a pastry case. Then...
Melt the butter in a large sauté pan (bearing in mind that what looks like a mountain of raw onion will cook down to a ¼ of its size) on a low heat- on a scale of 1 -10, I’d go for about 3.5.
Chuck in the bay leaves and the thyme and then add the onions.
Over the course of the next half an hour or so, stir the onions every so often, but if you’ve got the heat right there’s no chance of them catching or turning colour just yet. It’s during this stage that they’ll ooze their water, don’t panic, we knew that was going to happen.
As and when the onions start to take on colour (it’ll be the ones at the bottom of the pan first so you’ll have to go and look for them), scrape and stir frequently, probably for another hour or so until you have a big shiny mass of dark brown caramelised onions.
When you’re satisfied you have enough colour, and I urge you not to bolt too soon, tip them into a sturdy sieve sat over a bowl and let any excess butter drain off. Pick out the bay and the thyme. It wouldn’t matter if you left them to go cold, but don’t refrigerate them.
Now beat the eggs with the yolks together with a fork (…in a bowl) with half a teaspoon of salt for now, and some black pepper, add the cream and combine. Add the onions and mix thoroughly, using the fork to separate the onions. Taste it for seasoning - yes, I know its raw egg but so is Advocat – you telling me you don’t like a Snowball at Christmas!? Add more salt and pepper if you think it needs it.
Tip this into your pastry case, level the top with the back of a spoon (this is not a self-leveller) and shove it the oven for 25 mins at 180⁰C , after which time it should start to be browning slightly on the top, have no wobble left and the centre should feel firm. You could give it another 5min if you’re not sure as long as its not taking on too much colour. If it is, cover with some baking paper to take the brunt of the heat.
Let this cool slightly before eating or entirely before portioning.
Reheat it at 180⁰C for 10mins.