It's nearing the end of rhubarb season here in Massachusetts, and it's too bad, because it's such a unique and versatile ingredient. Left raw and alone, it's about as tart as you can get, but cooked down or baked into sweet treats, it's positively divine. While I've baked with rhubarb on many occasions before, I've never thought to pair it with white chocolate, but I came across a few recipes that suggested just that, so I gave it a try. The results? Phenomenal!
These bars have several different components that help create wonderful layers of flavor, but they're relatively simple to assemble which makes this recipe a no-brainer. From the buttery shortbread crust to the smooth white chocolate, the silky rhubarb filling, and the wonderful crumb on top - these bars have absolutely everything going for them.
One key part of this recipe is that the rhubarb is cooked prior to assembly, helping to break down it's fibrous strands, and also to mellow the tart/bitter flavor. You're left with a mildly sweet and mostly smooth rhubarb puree of sorts, that still has rhubarb strands throughout but that is much more palatable!
The overall flavor of these bars is unlike much else I've tried. It has such a unique combination of flavors and textures, and is a ton of fun to eat! There is definitely a pervasive buttery flavor, which accompanies the rich rhubarb and the sweet white chocolate. If you make these, don't expect them to last long!
Caramelized White Chocolate Rhubarb Bars adapted from Not Derby Pie
Shortbread Crust Ingredients 1 cup all-purpose flour 1/4 cup powdered sugar 1/4 teaspoon salt 8 tablespoons very cold unsalted butter, cut into small pieces
Filling Ingredients 1/2 pound (8oz) white chocolate
1 1/2 pounds (about 5 cups) 1-inch pieces rhubarb 1/3 cup plus 1 tablespoon sugar
Crumb Topping Ingredients 6 tablespoons unsalted butter, melted, plus room-temperature butter for pan 1 cup all-purpose flour, (spooned and leveled), plus more for pan 1/2 cup packed light-brown sugar 1/4 teaspoon salt
Directions For the shortbread: Preheat the oven to 350°. Line an 8 x 8 pan with parchment paper and set aside. In the bowl of a food processor, combine flour, sugar and salt, and pulse a few times to combine. Add butter, and pulse until dough starts to come together. Turn dough onto a lightly floured work surface, and gently turn it a few times make sure the dough is completely combined, and any stray bits of dough are incorporated.
Press the tart dough into the parchment lined pan, and make the dough as uniformly flat as possible. Poke the dough in several places with a fork to help anchor it, then back for about 20 minutes, until very lightly golden brown. Remove from the oven and let cool while you make the filling.
For the rhubarb filling: Combine rhubarb and sugar in a medium saucepan and heat over medium until the mixture starts to hiss and bubble slightly. Cover pan and cook 6-8 minutes, until rhubarb is completely softened. Once softened, remove lid and raise heat to medium-high. Cook an additional minute or two, until remaining juices evaporate. Stir rhubarb to break apart the individual pieces and create a uniform consistency.
For the crumb topping: Combine all ingredients in a small bowl, and use your fingers to mix them together. Make sure the crumble ingredients are completely incorporated.
Assembly: In the top of a double boiler, melt the white chocolate, then spread the white chocolate over the shortbread crust. Spread the rhubarb mixture over the chocolate, and sprinkle the crumb topping over the rhubarb. Bake for 50 minutes, or until crumb topping is golden brown and the rhubarb is sizzling. Remove from over and let cool at least one hour before serving.