I came to know rhubarb when I enrolled in graduate school at the University of Michigan. Rhubarb is a northern crop, certainly nothing I encountered in the more temperate clime of my Oklahoma upbringing. You can imagine my surprise when I started seeing it on Mexico City restaurant menus. Assuming it was imported, I was corrected by a chef friend who filled me in on how beautifully it grows in places like Cuernavaca and the chinampas of Xochimilco.
All kinds of Mexican rhubarb preparations are popping up, and this is one more I want to add to the collection. It’s an easy crumble tart with powdered jamaica flowers adding deep crimson color and complimentary tang to the rhubarb filling. And fresh ginger? That’s rhubarb’s new best friend.
INGREDIENTS
- For the crumble topping:
- 3/4 cup + 1 tablespoon (180 grams) sugar
- 3 cups (400 grams) all-purpose flour
- 1 1/2 teaspoons salt
- 7 ounces (200 grams) cold butter, cubed, plus extra for greasing the pan
- 1/2 cup (65 grams) toasted, salted pepitas (or pecans)
- For the filling:
- 3/4 cup (a little less than 1 ounce) Jamaica Flowers OR 2 tablespoons of ground hibiscus (I like Burlap & Barrel's Desert Hibiscus)
- 1/2 cup (110 grams) sugar
- 3 tablespoons (33 grams) cornstarch
- 1 tablespoon finely grated fresh ginger
- 1/2 teaspoon (1.5 grams) ground allspice
- 1/2 teaspoon (1.5 grams) black pepper
- 5 cups (650 grams or about 1 1/2 pounds before trimming) rhubarb, cut into ½-inch pieces
- For serving:
- A cup of Mexican crema, sour cream or creme fraiche
INSTRUCTIONS
Make the crumble. In a food processor, combine the sugar, flour, salt and butter. Pulse until it looks like very coarse sand, then run the processor just until the mixture starts to clump. Generously butter the bottom and sides of a 9-inch springform pan; line the bottom with a round of parchment paper. Scrape ⅔ of the mixture into the bottom of the pan and pat it firmly into an even layer. Add the pepitas to the remaining crumble mixture in the food processor and pulse until they are coarsely chopped. Set aside for topping.
Make the filling. Turn on the oven to 375 degrees. In a spice grinder (or with a high-speed blender like a Vitamix), pulverize the jamaica. Use a small pastry brush to scrape the powder into a large bowl (you should have about 2 tablespoons of powder). Add the sugar, cornstarch, ginger, allspice, black pepper, and rhubarb. Stir to combine everything thoroughly, then scrape the mixture into the pan and spread it evenly. Top the rhubarb mixture with an even layer of the crumble mixture. (I like to squeeze small handfuls of the crumble before breaking them up over the rhubarb, to give the finished tart a rustic “peaks and valleys” look.)
Bake and serve. Bake in the middle of the heated oven for 45 to 60 minutes on a rimmed baking sheet to catch any drips, until the top is a rich golden and you see a little a little rhubarb bubbling up through the top crust. Cool for at least 30 minutes for the crumble crust to fully set, then run a sharp knife around the edge, unmold, cut and serve with crema or ice cream. The tart can be baked as much as a day or two ahead (if more than a few hours, refrigerate it), then gently warmed before serving.
