For the pastry:
- 250g plain flour, plus extra for dusting
- 50g icing sugar
- 150g unsalted butter, in pieces
- 1 free-range medium egg
- 1 free-range medium egg yolk, lightly beaten
For the rhubarb filling:
- 6 rhubarb stalks, de-strung if necessary and cut into 1 cm lengths
- 180g sugar, or to taste
- 1 orange, finely zested and juiced
For the crumble topping:
- 250g plain flour
- pinch sea salt
- 200g unsalted butter, cold and in pieces
- 200g soft light brown sugar
- 75g rolled oats, (or oatmeal)
- few drops pink food colouring
- mint, shredded, to finish (optional) or lemon thyme, to finish (optional)
1 To make the pastry, sift the flour and icing sugar together into a food processor. Add the butter and pulse until the mixture resembles breadcrumbs. Add the whole egg and pulse briefly until the dough just comes together. Turn out onto a lightly floured surface, knead gently, then flatten into a round. Wrap in cling film and chill for 30 minutes.
2 In the meantime, for the filling, put the rhubarb into a heavy-based saucepan with the sugar and orange zest and juice. Bring to a simmer, lower the heat and cook gently for 10–15 minutes until the rhubarb is softened but still holding its shape.
3 Meanwhile, to make the crumble, sift the flour and salt into a bowl. Add the butter and rub in with your fingertips until the mixture resembles coarse crumbs. Stir in the brown sugar, oats and a little food colouring – to give the crumble a nice pastel pink colour. Cover and chill for 20 minutes.
4 Roll out the pastry on a lightly floured surface to a 3–4 mm thickness and use to line 4 individual flan tins, 7.5 cm in diameter and 2.5 cm deep. Trim the excess pastry away from the edges. Place in the fridge to rest for 15 minutes before baking. Heat the oven to 180°C.
5 Line the pastry cases with baking parchment and add a layer of baking beans. Bake the pastry cases ‘blind’ for 10 minutes, then remove the paper and beans and bake for a further 10 minutes until the pastry is cooked through. Remove the paper and beans and brush the inside of the hot pastry cases with the beaten egg yolk to seal. Set aside on a wire rack.
6 Scatter the crumble on a baking tray and bake for 6–8 minutes until golden and crispy.
7 To serve, warm the rhubarb compote, if necessary, and use to fill the tart cases. Scatter the crumble evenly over the surface. Finish with a sprinkling of herbs or leave plain if you prefer. Serve with a scoop of vanilla ice cream or pouring cream.