Since Henri Ollivier made the maiden voyage in 1828 the beautiful pale pink Roscoff Onions have arrived on our shores between October and March from the fields of Bretagne. The 19th Century road and rail network in Northern France was poor and the journey was perilous and long for farmers seeking to sell their harvest. The journey to England was similar in distance and small sailing and steamer ships made it a viable option for the ‘Onion Johnny’. England soon provided a profitable market-place for the Roscoff Onion and the Onion Johnny became the stereotypical image of the Frenchman: with the striped top, bicycle and plait of onions.
During the 1929 the Onion Johnnies imported over 9,000 tonnes of Roscoff Onions into Britain. The trade reached its peak during the 1920’s but the Great Depression of the 1930’s saw the quantity of Roscoff Onions imported fall to 3,000 tonnes in 1934. The trade was impacted further following the Second World War, which imposed import restrictions on produce. Sadly, by 1973 only 1,100 tonnes of Roscoff Onions reached Britain’s shores and the decline continued until only 20 tonnes were imported each year by the end of the 20th Century. The Roscoff Onion trade inspired the creation of Brittany Ferries in the 1970’s.
The Roscoff Onion trade has started to increase following a long period of decline. A museum dedicated to the Onion Johnny opened in Roscoff in 2004 and a two-day Onion Festival is held every summer. The Roscoff Onion has been awarded the French Appellation D’Origine Controlee (AOC) designation.
The Roscoff Onions can only be grown in specific soil types and are rarely found outside the Roscoff area. They are planted between mid-February and mid-April and harvested from August onwards and then dried. The Roscoff Onion is rich in Vitamin C and has a long shelf-life. They are similar in size to a plump shallot, they have a crisp texture, and they are mild and sweet in flavour.
Roscoff Onions are a real delight and they are wonderful raw in vinaigrettes, or braised alongside a joint of lamb, or slowly roasted with butter and thyme then topped with thick slices of Cheddar or Tunworth cheese and grilled (perfect when served with lambs lettuce, drizzled with good cider vinegar, and a hearty wedge of walnut sour dough to mop up the cooking juices!).
I was wandering around the Farmer’s Market in Marylebone about 6 years ago when I first encountered these beautiful onions. I spent some time considering the best way to showcase their exquisite flavour and decided that one option could be a variation of an old Patricia Wells recipe: Onion & Parmesan Gratin. I adapted this recipe to form a shallow tart, the base of which is formed from a thin and crisp pizza dough. The Roscoff Onions should be sweated (cooked gently in their own juices, a little water, and some butter or oil) to bring-out their natural sweetness. This tart can be made the day before (to the point that it is ready to bake) and then refrigerated for 24 hours (just bring it bake up to room temperature prior to baking). You could use a swiss-roll tin (approx 23cm x 33cm) or make the tart flat as you would with a pizza.
350g Pizza dough (preferably the dough should have rested in the fridge for at least 2 days before baking)
700g Roscoff Onions (finely sliced)
30g Extra Virgin Olive Oil
2tsp Fresh Thyme leaves
100g Creme Fraiche
1 Large Egg
120g Cheese (grated)*
Salt & Pepper
*Use the cheese of your choice, but choose one which will melt! I used a combination of Tunworth and Comte, because that’s what I had in my fridge at the time.
Pre-heat oven to 280C
Melt the butter with the olive oil and 50ml of water in a large frying pan over a low heat. Add the slice onions and a generous pinch of salt, then cover the pan. Sweat the onions until they a meltingly soft and sweet but with no colour; this will take at least 40 minutes. Add a little more water if the pan becomes dry or the onions start to sizzle. When the onions are soft remove the lid and continue to cook the onions until the moisture has evaporated (without browning the onions), then remove the pan from the heat.
Meanwhile mix the creme fraiche, the egg, the cheese, and some freshly ground white pepper, in a medium mixing bowl. When the onions have cooled add them to the creme fraiche mixture.
Lightly flour a sheet of baking parchment and roll-out the pizza dough into a rectangle measuring approximately 30cm x 40cm. Either place the baking parchment and the dough onto a baking sheet or into a swiss roll tin.
Spread the onion and creme fraiche mixture over the dough, right to the edges.
Bake on the bottom shelf of the oven for 30-40 minutes until the dough is cooked and golden brown.
Serve the tart warm with chutney on the side, or a lentil salad, or a seared rib-eye steak.