This is the final post for rhubarb week and I have saved the best for last. I have actually had this recipe in my back pocket for at least a year actually, waiting for the right time of year to post. Rhubarb was a regular feature in my childhood, as a family we grew it in our garden and regularly had it for dessert after Sunday lunch. The main difference between then and now is that our homegrown variety was definitely not forced rhubarb, it was thick, green, stringy and so incredibly sharp, almost sour in flavour. Whilst this style of rhubarb was far from my favourite it was something my mum loved. When I made these tarts for her she begged me for the recipe, and because I am a terrible son, who is ridiculously forgetful, it took me a whole year to send her the recipe. I would like to think it is worth the wait but that is just my big head showing!
Now lets talk about the tricky part of this recipe. The creme brûlée filling is made on the stovetop, slowly stirring a custard until thickened which is theoretically simpler than baking. But and it is big but mastering the finished texture is a little tricky to get spot on. I would actually suggest that rather than using a temperature you should use visual clues. You need to cook the custard slowly for about 10-15 minutes or until the whisk creates tracks in the custard. If you undercook the custard it wont set as firm and wont give you that fabulous set custard of a creme brûlée.
220g buckwheat flour
30g caster sugar
pinch of salt
125g unsalted butter, diced and chilled
1 large egg yolk
Cardamom Creme Brûlée
1/2 vanilla pod or 1 tsp vanilla bean paste
1tsp ground cardamon
500ml double cream
6 large egg yolks
45g caster sugar, plus extra for brûlée topping
1 batch roasted rhubarb (recipe here)
3 tbsp roughly chopped pistachios
To make the creme brûlée filling scrape the seeds from the vanilla pod and place into a bowl along with the cardamon, egg yolks and sugar, whisking together. Place the cream into a pan and bring to a simmer. Pour the cream onto the egg mixture and whisk to combine. Place the bowl over a pan of gently simmering water and stir constantly with a whisk (dont whisk vigorously, just stir gently, regularly scraping the bottom of the bowl) for about 10-15 minutes or until the custard has thickened the mixture should be the texture of a thick pouring custard. Remove the bowl from the pan and press a sheet of clingfilm onto the surface of the custard and refrigerate overnight.
To make the pastry place the flour, sugar and salt into the bowl of a food processor and pulse to combine. Add the butter and pulse until the mixture resembles fine breadcrumbs. Add the egg yolk to the processor and pulse to combine. Squeeze some of the mixture together and if it holds its shape it is ready but if it crumbles apart pulse in a little water, a teaspoon at time until the dough holds together (normally it takes about 1-2 tbsp to bring the pastry together). Tip the dough out onto the work surface and bring together with your hands, forming into a short, fat sausage shape. Wrap the dough in clingfilm and refrigerate for at least an hour before using.
Preheat the oven to 180C (160C fan) and line a baking tray with parchment paper.
To form the tart shells remove the pastry from the fridge and cut into six discs. Roll each disc of pastry between parchment paper until about 2-3mm thick. Gently drape the pastry into a 10cm loose bottomed fluted tartlet tin, pressing into the corners. Trim off the excess and place onto the baking tray. Repeat with the remaining pastry and refrigerate for an hour or until firm. Line the tart shells with a piece of crumpled parchment paper and fill with baking beans or rice and bake in the preheated oven for 25 minutes. Remove the parchment and the baking beans and bake the tarts for a further 5-10 minutes or until golden brown. Set aside to cool.
Once the pastry has cooled remove the creme brûlée filling from the fridge and divide between the tart shells. Top the tarts with a even layer of caster sugar and using a kitchen blowtorch caramelise the sugar. Place the tarts into the fridge for about an hour before serving (any longer and the crisp layer of sugar will start to melt). Preheat the oven to 190C (180C fan).
Whilst the tarts are chilling roast the rhubarb as in this recipe here.
To serve top each tart with a few pieces of the rhubarb, with a little of the syrup, and a sprinkling of pistachios.