Rhubarb comes into season just as we need it, bringing with it hope: when the days have been too short for too long, rhubarb appears, in glorious technicolour, an acid pink that is nature’s nod to its sweet-sour qualities. The rhubarb season is a long one, that starts abruptly after Christmas and stretches luxuriously into June. It is especially long because it spans the forced rhubarb season (January through to March/April), and the field rhubarb season (April through June). Not like the elusive blood orange that appears teasingly with its blushing skin and ruby innards, only to disappear as soon as you remember the season has arrived. No such fear with rhubarb, which once arrived, is here to stay. Or at least until June.
Rhubarb has been forced since the 1800s: a process, originally accidental, now designed, by which rhubarb is grown in complete darkness meaning it doesn’t develop the green or fibrous qualities it otherwise would. It is grown in the Rhubarb Triangle (a nine miles squared area in West Yorkshire). The rhubarb is initially grown in the fields, but then transferred to dark, heated sheds, where its stalks turn crimson and tender. Traditionally – delightfully – the rhubarb is picked by candelight to avoid light exposure.
It’s trite to say that spring brings hope and heralds new starts, but that doesn’t make it any the less true. New starts which are sweeter and fresher than those of January, when resolutions are made in a fog of hungover regret, and destined for failure. Spring feels like a second chance. I am happy to crown rhubarb the mascot of spring, of hope. We, like forced rhubarb, have survived the frost and the darkness, and these hot pink, slender shoots are our reward. It propels us into the sunny safety of summer, and then disappears until we need its cheer again.
So here is my rhubarb and custard tart: a sweet shortcrust, cut through with orange zest, topped with a silken, vanilla speckled crème patissière which, when baked, firms up to give just the merest hint of wobble. Use the brightest and best rhubarb you can find: firm, not floppy, and a vivid pink. The roasted rhubarb retains its shape and integrity, and although there is a little bit of sugar to encourage the sweetness, it still has sharpness, but with a soft, almost floral flavour underneath.
You could bake the rhubarb into the tart, and it would be delicious, but I love the way this rhubarb stands proudly above the custard, with each mouthful containing rhubarb and custard, distinct from another, the soft creamy custard set against the sharp sweetness of the rhubarb rather than muddled together. The roasting will produce some of the most gorgeous rose-coloured rhubarb juice you are ever likely to find: drain it from the pan, and use it as the base for a gin cocktail. It is glorious.
I use a long rectangular tart tin for this, about 30cm by 10cm, and the quantity of ingredients given below broadly reflects that. This, I’m sure, would work equally well in a round tart tin, and would recommend that you use one approximately 25cm in diameter: you may need to bake the custard for very slightly longer to make sure that it has set in the middle. It goes like this…
Rhubarb and Custard Tart
Makes: 8 elegant portions, or 4 fat square portions
Takes: 1 hour (including cooling)
Bakes: 35 minutes
For the pastry
170g plain flour
100g butter, cold, cut into cubes
1 tablespoon icing sugar
1 egg yolk Ice cold water
Zest of 1/2 orange
For the rhubarb
Zest of 1/2 orange
2 tablespoons of caster sugar
For the custard
325ml whole milk
3 medium egg yolks
75g caster sugar
1 tbsp plain flour
1 tbsp cornflour
1/2 vanilla pod
1. First, make your pastry. In a large bowl, rub the flour, butter and icing sugar (and orange zest, if using) until it looks like fine breadcrumbs. Add your egg yolk to the bowl and cut into the pastry with a knife. When it starts to come together, use your hands to bring it into a ball of dough. If it’s struggling, add a few drops of ice cold water. Knead very briefly only until the dough is just smooth. Flatten into a disc, wrap in clingfilm and rest in the fridge for 20 minutes.
2. Once rested, roll the pastry out to the thickness of a pound coin and line your pastry tin with it. You can do this by flouring a rolling pin, rolling the pastry onto it, and then slowly draping it over the tin. Gently push into the shape and pattern of the tin, and then roll your rolling pin slowly but firmly across the top of the tin: this will neatly cut off the excess pastry. Prick all over with a fork, and place in the freezer for 30 minutes.
3. Pre heat the oven to 200°C. Remove the pastry from the freezer, line with baking paper, and add baking beans or uncooked rice. Cook for 10 minutes, remove the baking paper and beans and return to the oven for five minutes until the base is golden, but not brown.
4. Roast the rhubarb. Cut your rhubarb into batons about 2.5-3 inches long (but be led by the size and shape of your pan). Place in a single layer on a lined baking tray. Sprinkle with the sugar, zest half an orange over the top of it all, and roast for 10 minutes until tender, but retaining its shape. Reserve the juice for gin, and thank me later.
5. Now make the custard: split the vanilla pod down the middle, and scrape the seeds out using the back of your knife and add them, along with the pod itself, to the milk. Place the milk in a pan, and bring it gently to steaming. Once boiling, remove the vanilla pod. In a large bowl whisk the egg yolks with the sugar until pale and then whisk in the flour and cornflour.
6. Pour about half of the hot milk over the egg-sugar-flour mix, and stir with the whisk whilst doing so. Return the custard mixture to the pan and heat gently, stirring throughout. Keep heating and stirring until the mixture thickens and just begins to blip: you need the mixture to have reached boiling point. If your mixture becomes lumpy (this can happen if your heat is too high), don’t panic, just push it through a sieve before cooling. Place in a bowl and cover with clingfilm, which should touch the surface of the custard.
7. Assemble your tart. Using a spatula, smooth the custard into the tart and carefully lay the rhubarb on top, as neatly as you can. I use a palette knife for this. Bake in the oven at 170 degrees for about 15 minutes, until the custard is set, but retains a slight wibble.
8. Ta Dah!
Icing on the Cake
I tend to serve this tart just as it is, a slab of hot pink and pale primrose on a white plate, but it would be lovely with orange zest-spiked creme fraiche, drizzled with the reserved rhubarb juice.