Preheat the oven to 410º F (210º C).
1. In a medium-sized ovenproof bowl, such as a Pyrex bowl, combine the butter, oil, water, sugar, and salt.
2. Place the bowl in the oven for 15 minutes, until the butter is bubbling and starts to brown just around the edges.
3. When done, remove the bowl from oven (and be careful, since the bowl will be hot and the mixture might sputter a bit), dump in the flour and stir it in quickly, until it comes together and forms a ball which pulls away from the sides of the bowl.
4. Transfer the dough to a 9-inch (23 cm) tart mold with a removable bottom and spread it a bit with a spatula.
5. Once the dough is cool enough to handle, pat it into the shell with the heel of your hand, and use your fingers to press it up the sides of the tart mold. Reserve a small piece of dough, about the size of a raspberry, for patching any cracks.
(Paule takes a fork and reinforces the dough to the sides, which I didn’t find necessary.)
6. Prick the dough all over with the tines of a fork about ten times, then bake the tart shell in the oven for 15 minutes, or until the dough is golden brown.
7. Remove from the oven and if there are any sizable cracks, use the bits of reserved dough to fill in and patch them.
I find it best to pinch off a small amount of the reserved dough, roll it gently between your fingers to soften it, then wedge it into the cracks, smoothing it gently with your pinky.
8. Let the shell cool before filling.