- Preheat oven to 400°F with rack in middle.
- Stir together orange juice, lime juice, and sugar in a bowl. Add rhubarb and let stand, stirring occasionally, 10 minutes.
- Meanwhile, cut pastry in half lengthwise, then roll out each piece into an 11-by 7-inch rectangle on a lightly floured surface with a floured rolling pin. Arrange pastry rectangles side by side on an ungreased large baking sheet.
- Make a 1/2-inch border around each pastry rectangle by lightly scoring a line parallel to each edge (do not cut all the way through). Prick pastry inside border all over with a fork.
- Strain rhubarb mixture through a sieve set over a bowl, reserving liquid. Top 1 pastry rectangle (within border) with half of rhubarb, overlapping slices slightly. Repeat with remaining pastry and rhubarb.
Bake until pastry is puffed and golden (underside of pastry should also be golden), about 30 minutes.
Meanwhile, boil reserved rhubarb liquid in a small saucepan, skimming foam if necessary, until reduced to about 1/4 cup, 15 to 18 minutes.
- Transfer tarts to a rack. Brush rhubarb and pastry with glaze and sprinkle with zest.
Long story short, I attempted this recipe due to the convergence of a challenge from an old friend (who, after seeing my koi pond pie, commented that I should next make something reflecting my namesake/internet handle) and another friend having spied cheap rhubarb for sale in another state and hand-carrying a pound's worth of stalks back for me. I then promptly ended up doing a whole bunch of substitutions, both intentional and unintentional, and in the end determined that this is really just a sweet rather than savory pizza-like dessert that is pretty forgiving of whatever you want to do with it. Thus, if you wish to try it, I wish you many happy experiments!
Part of the reason I started baking was because I like my goodies to be less obviously sweet - I want to taste the flavor, not just the sugar. So most of these recipes will have the sugar dialed down.