01 -
Toss your flour with salt in a big bowl. Drop in the cold butter cubes and quickly squish them between your fingers or use your fork until it looks kind of crumbly, like little pebbles.
02 -
In a little bowl, stir together the egg yolk and 30 ml of cold water. Pour that into the crumbly flour stuff. Mix with your fork and add more cold water, just a spoon at a time, until it barely forms a dough.
03 -
Squish the dough together into a disk, wrap it up tight in plastic, and stick it in the fridge for at least half an hour so it stays cool.
04 -
Slice your rhubarb into chunky pieces. Melt the butter and sugar in a deep, oven-safe skillet (25 cm) over medium heat. Pack the rhubarb pieces snug into the pan on top of the caramel. Let it cook gently, on low, for about 20–30 minutes, until it gets a little golden and most of the juices are gone.
05 -
Crank your oven up to 190°C and let it preheat.
06 -
Roll out that chilled dough on a floured counter, a bit bigger than your pan. Lay it over the rhubarb caramel, tucking the edges down to trap the fruity goodness underneath.
07 -
Pop your skillet in the oven and bake for 25–30 minutes. You're looking for a crust that's crisp and deeply golden.
08 -
Once it's done, take it out and let it rest for five minutes. Put a plate on top, flip the whole thing over in one motion, and the tart should drop right onto your plate.
09 -
Cut into slices and pass it around hot, with a scoop of vanilla ice cream or a bit of softly whipped cream if you want.