Preheat oven to 410°F. Measure out your flour and keep in a bowl, set aside.
In a medium-sized ovenproof bowl, such as a Pyrex bowl, combine the butter, oil, water, sugar, and salt.
The original recipe called for placing the bowl in a 410°F oven for 15 minutes, until the butter is bubbling and starts to brown just around the edges. I used the microwave on high for 8 minutes.
When done, carefully remove the bowl from oven (or microwave), dump in the flour and stir it in quickly with a wooden spoon until it comes together and forms a ball, which pulls away from the sides of the bowl.
Divide the dough to 6 individual (5-inch round) tart shells (I use an ice cream scoop) or two 9-inch tart shells.
Once the dough is cool enough to handle, pat it into the shell with your fingers and press it up the sides of the tart mold.
Prick the dough base all over with a fork. Place the tart shells on a baking tray and transfer to the oven. Bake for 15 minutes, or until the dough is golden brown.
Let cool and spread with any filling you like.
Notes
Adapted from David Lebovitz via Paule Caillat, who teaches cooking classes at Promenades Gourmandes in Paris, France.