Caramelized Red Onion and Rocket Tartlets Recipe by Mary Berry

This caramelized red onion and rocket tartlets recipe is easy to make with filo pastry – there’s no rolling out, and its crisp texture makes a great contrast to the soft, creamy filling. You can prepare the tin and filling ahead.

Serves 4


– 1 large red onion
– 20g (3⁄4oz) butter
– 2 tsp olive oil
– 1 large egg
– 150ml carton double cream
– salt and freshly ground black pepper
– 15g (1⁄2oz) rocket leaves
– 25g (scant 1oz) Parmesan cheese, coarsely grated
– 25g (scant 1oz) mature Cheddar cheese, coarsely grated

For the filo pastry cases
– 25g (scant 1oz) butter, melted
– 2–3 large sheets shop-bought filo pastry
– 4 tsp fresh thyme leaves

Special equipment: 4-hole Yorkshire pudding tin


1. Finely slice the onion. Heat the butter and oil in a large, non-stick frying pan until the butter has melted. Add the onion slices and fry over a medium–low heat for about 15 minutes, stirring only occasionally, until soft and caramelized. Remove the onion, drain on kitchen paper, and set aside to cool. (See Keys to Perfect tip: Caramelize the onion.) Preheat the oven to 190ºC (fan 170ºC/375ºF/Gas 5).
2. Prepare the filo pastry cases: brush a little of the melted butter in the hollows of the Yorkshire pudding tin. Using a sharp knife, cut 16 squares, measuring 11 x 11cm (41⁄2 x 41⁄2in), from the filo sheets (how many you get from each sheet depends on the brand of filo). Layer up 4 filo squares per hole, each at an angle to the previous squares, brushing melted butter and sprinkling thyme over each one. Scrunch up the pastry edges to add a bit of height. (See Keys to Perfect tip: Make crispy filo cases.)
3. In a small bowl, beat the egg, then stir in the cream and some salt and pepper. Roughly chop the rocket, setting aside just a few leaves for garnish. In a separate bowl, combine the two cheeses.
4. Carefully spoon the onion into the pastry cases. Scatter over half the cheese and the chopped rocket. Pour in the egg mixture, then top with the rest of the cheese.
5. Bake for 15–20 minutes or until the filling is just set and starting to turn golden brown at the edges. Remove from the tin and serve warm, garnished with the reserved rocket leaves.

Keys to Perfection:

Caramelize the onion
1. Peel the onion. Using a sharp chef’s knife, quarter the onion lengthways. Cut the hard root from the base, then slice down each quarter lengthways into thin slices. This will give small, delicate pieces that are suited to the scale of the tartlet cases.
2. It’s important to fry the onion in a mixture of butter and oil. The butter adds flavour and the oil helps to stop the butter from overbrowning during the long cooking time needed to caramelize the onion. Fry the onion very slowly to bring out its sweetness. Stir occasionally to prevent it from burning, but not too often as you want it to start browning where it’s in contact with the pan.
3. As the onion starts to turn brown and gets a bit sticky, stir so it doesn’t burn and to bring the paler bits of onion to the bottom of the pan so they can also get brown. Scrape up the browned bits at the bottom of the pan using a spatula.
4. When the onion is done, it should be well reduced and evenly caramelized to a rich deep brown colour. Its flavour will become sweeter and more intense during the cooking process. Remove it using a slotted spoon and drain on kitchen paper.

Make crispy filo cases
1. Stack the filo pastry sheets on a board and cut out the 16 squares, each 11 x 11cm (41⁄2 x 41⁄2in), using a sharp knife in order to prevent the pastry from tearing as you cut. Filo pastry dries out extremely quickly and becomes very brittle, so keep the filo covered with a damp tea towel or cling fi lm until you start lining the tins, which you should do as soon as possible.
2. For each case, brush one square of filo with butter and lay it in a hole in the buttered tin; the edges of the pastry square should extend over the rim. Sprinkle with thyme. Repeat for the three remaining squares of filo, laying each at an angle to the previous ones so they overlap, and buttering and sprinkling thyme over each layer. Layering the filo like this strengthens the pastry cases.
3. To add a bit of height and interest to the pastry cases, ruffle up the edges. Use your thumb and forefinger to bring up the sides so they’re upright, then turn over the edges in small, soft folds, keeping the sides raised to maintain height. A bit of irregularity with the folds is fine and adds character to the cases.

Buying and using filo pastry:This paper-thin pastry is not easy to make, but it’s widely available in packets containing a number of ready-made sheets. Sizes of fi lo sheets can vary according to the manufacturer, so for this recipe you may need more than the number of sheets specified to be able to cut out enough squares. Careful handling is important. The sheets are extremely thin, so try not to split or tear them, as it may allow the filling to leak. If the pastry does tear, patch it up with another piece of buttered filo.



mary-berry-feat-1Mary Berry, CBE is one of the UK’s best-known and most respected cookery writers and television presenters. She has over 80 books to her name and over 6 million sales worldwide. Mary is a judge on the BAFTA award winning The Great British Bake Off series for the BBC, and a presenter on her own TV series Mary Berry Cooks. She specializes in family food, no fuss, practical and foolproof.

Mary Berry is the author of several DK books including the bestselling Mary Berry’s Complete Cookbook, which has sold over 1 million copies worldwide. In her new book Mary Berry Cooks the Perfect features over 100 exciting recipes, from quick family suppers to rustle up after work to more impressive dishes for entertaining.What sets this book apart is Mary’s ‘Keys to Perfection’. For each recipe Mary identifies the crucial parts you need to get right to guarantee the best results

Mary Berry Cooks the Perfect is published by DK, for more information click here.

Mary Berry

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