You can make this tart with any summer berry or with a mixture of berries.
For the shortbread crust, whisk together in a bowl or process in a food processor for 10 seconds:
I find that when I'm trying to write recipes for our website, I'm conflicted about what to do. It's not that I don't have lots of ideas. It's that I'm never sure whether to be creative and spontaneous or traditional.
As someone who does a lot of cooking, I enjoy flying by the seat of my pants. As you might imagine, we have a pretty well-stocked pantry, so when I get the urge to go off script and add something, it's not that I expect you to do the same. It's that I expect you to follow your own taste buds and pantry and decide whether to go on my wild adventure or not.
And so when I tell you to add Angostura bitters to your rhubarb pie, you might think I've gone too far, but I can assure you that the results are completely delicious and not at all strange. I wish I had been the first to think of this ingredient as an addition to pie, but the first place I saw it was in the Four and Twenty Blackbirds pie cookbook. Then, in Emily Hilliard's guest post, she added bitters to a peach-blackberry pie.
I am not one to argue with innovation in the pie realm. At worst, I figured I would just have to pile on more ice cream to tone down the bitter flavor. But as it turns out, this pie is perfectly, wonderfully delicious à la mode or au naturel. The bitterness from the Angostura is very mild--more than bitterness you get a hint of spice and complexity. I also went for it and added orange zest and ginger to the filling because they play well with rhubarb. No pressure, though. This is your pie, and you should make it in your style.
I love the chocolate crust here. It's not overwhelmingly chocolaty, but it adds richness and contrast, especially if your rhubarb is bright pink. A plain piecrust will work fine here, though.
Other rhubarb recipes you might enjoy: Roasted Rhubarb, Rhubarb Chess Pie, Rhubarb Mostarda
For the crust, Combine:
2 cups all-purpose or pastry flour
1/2 cup cocoa powder, natural or Dutch-process, sifted
(2 tablespoons sugar)
1 teaspoon salt
12 tablespoons (1 1/2 sticks) cold butter, cut into small pieces
1/4 cup shortening or coconut oil
Cut in the fat until it is the size of small peas (visualize small peas). Add:
4 tablespoons water mixed with 2 tablespoons vinegar, ice cold
Knead the water into the dough until it just comes together. The mixture is wet enough when you squeeze a handful of it and its comes together in a smooth but not sticky ball. It may be very slightly crumbly. This is okay. However, if it doesn't seem anywhere near coming together and is dry and floury, you may need to add more water. The one thing you want to avoid, though, is adding so much water that the dough is sticky.
Divide the dough in two, press the dough into flat disks, wrap tightly, and refrigerate for at least 1 hour and up to a few days. It's never a bad idea to make pie dough ahead of time. If you have 15 minutes to spare, you can make pie dough and set it aside for when you have time to make pie.
After chilling, let the dough sit at room temperature for 10 minutes. Roll out one of the rounds into a circle roughly 3 to 4 inches larger than your pan. Transfer the dough to a 9-inch pie pan and press it into the corners (I realize there are no "corners" in a circle, but work with me here). Trim the edges, leaving one inch of overhang. Place in the refrigerator to chill while you make the filling.
For the filling, combine in the bowl of a food processor:
1 cup sugar
Zest of one orange
A 2-inch piece of fresh ginger, peeled and grated
(Seeds of one vanilla bean)
Pulse until the sugar is orange and the vanilla bean is dispersed. Dump this into a mixing bowl with:
2 pounds rhubarb, cut into 1/2 to 1-inch pieces
1/2 cup brown sugar
1/4 cup cornstarch or arrowroot
1 tablespoon Angostura bitters
1/2 teaspoon salt
Stir to combine. Let the filling sit as you roll out the second piece of dough.
Roll out the top crust just like you did the bottom crust. Here you have a lot of options. You can just do a simple top crust with a vent for steam. You can do a lattice. You can do anything you want. Choose your adventure. Top the pie with the crust. Seal and crimp the edges. To set the crust, refrigerate the assembled pie for 30 minutes. Preheat the oven to 425°F.
Remove the pie from the refrigerator. Brush with:
One egg beaten with 1 teaspoon water and a pinch of salt
Place the pie on a baking sheet in the oven. Bake for 20 minutes. Reduce the oven temperature to 350°F. Bake for an additional 40 to 50 minutes or until the filling is nice and bubbly and your kitchen smells amazing.
Allow the pie to cool completely before slicing if you want neat slices. If you don't care, then go for it.