Method:

1) Preheat oven to 200°C (180°C fan).
2). To make the pastry: put the plain flour, 7 Tbsp of oil, 40g of sugar and a pinch salt in a bowl. Mix with a clean hand.
3). Add the water, mix again, the knead for three minutes.
4). Shape into a ball, and refrigerate to rest for 15-30 minutes.
5). When pastry has rested, put it between two sheets of baking paper and flatten gently. Roll out to 3mm thick and just larger than a loose-bottomed, non-stick 23cm tart tin.
6). Peel off the top sheet of paper, place a hand under the bottom sheet and flip the pastry on top of the tart tin - don't worry if it cracks or breaks. Peel off and keep the remaining paper.
7). Press the pastry into place, cut away the overhang and use the offcuts to fix any cracks.
8). Prick the base all over with a fork, crumple up the reserved paper, unravel it and put it in the tart case. Fill with baking beans, then bake for 25 minutes, until crisp and lightly golden. Remove and leave to cool. Leave the oven on.
9). To make the fragipane filling, mix everything except the rhubarb in a bowl until well combined.
10). When the tart is cool, lift out the paper and the beans, scrape the frangipane mix into the shell and smooth with the back of a spoon.
11). Now decorate as you wish: cut the rhubarb to size to lay strips across the tart, or cut it into shorter lengths and tesselate. The latter is more fun!
12). Sprinkle the top of the tart with an extra tablespoon of caster sugar, then bake for 40-45 minutes, until the filling is starting to bronze and the rhubarb is tender.
13). Leave to cool a little before cutting and serving. Can be served with vegan custard or whipped coconut cream.