How to make onion tart tatin

Sweet red onions make the perfect companion for a pastry, says Julia Platt Leonard

(Julia Platt Leonard)

A slice of savoury tart and a green salad is a perfect meal. It’s satisfying and comforting and best of all, it can be made ahead of time. Onions – especially sweeter red ones – are an ideal companion for pastry. Cook them on the stove first to soften and they become candied and jammy and caramelised.

A hit of balsamic vinegar and some woody herbs – thyme here, but sage would be a star too – and you cut through some of the sweetness. Puff pastry is a buttery indulgence but a green salad with a mustardy vinaigrette balances that out.

I wouldn’t dream of making my own puff pastry when you can buy some very good ones at the shops but if you’re so inclined, please do.

The only slightly hair-raising moment is when you flip the tart over. The important thing is to let the tart sit for ten minutes or so after you take it out of the oven. If you try to do it immediately, you may find the onions stick to the pan.

The second point is to use a non-stick pan if you can – it makes life easier. I have a frying pan with a removable handle which works a treat.

Make sure your cutting board or plate is larger than your pan. Place it over the pan so it’s completely covering it. Grasp the pan and board (or plate) securely and flip with confidence. And don’t worry if any onion wedges remain: simply lift them off and place them back on the tart. Your guests will be none the wiser. Besides, they’ll be too busy tucking in, to even notice.

(Julia Platt Leonard ) (Julia Platt Leonard)

Onion tarte tatin

Serves 4-6

450g small red onions
30g unsalted butter
​1tbsp olive oil
​1tbsp balsamic vinegar
A few sprigs of thyme
Salt & pepper
​500g puff pastry

Preheat the oven to 220C. Place a 28cm oven-proof pan on the stove. Put the butter and olive oil in the pan over medium heat to melt the butter. Meanwhile, peel the onions, slice in half through the stem end and root end. Slice each half into thirds, so you have six wedges per onion. Place the onion wedges in the pan, root end facing out, forming a circle. Repeat, creating an inner circle and then fill in any remaining gaps in the centre. The onions should fit together snugly, slightly overlapping. As they cook they’ll shrink a bit. Season with salt and pepper.

Cook on the stove until the onions are soft. Sprinkle the tablespoon of balsamic vinegar over the onions and dot with some thyme leaves. Remove the pan from the stove and allow to cool slightly while you roll out the pastry.

Roll the pastry into a circle that is slightly larger than the pan. Tuck any excess in, to create a neat edge.

Place the pan into the hot oven and bake until the pastry is puffed and brown. Remove and let the tart sit for 10-15 minutes. Place a cutting board or plate that is larger than the pan, on top of the pastry and flip over so the onions are on top. If some of the onions stick in the pan don’t worry – simply lift them off and place them back onto the pastry. Sprinkle a few more thyme leaves on top to garnish and serve.

@juliapleonard