My in-laws have a 40 year old rhubarb patch.
It’s an absolute bear - a solid 50 square feet of giant leaves and ruby stalks, the kind of thing that makes you wonder how grocery stores can charge $4 a pound for what is clearly a weed left over from the cretaceous. I can practically see a brachiosaurus gently tugging on the stalks to pluck them from the plant. And who can blame them? It’s the perfect harbinger of spring - lush, colorful, and tart - exactly what we need to go with those first radishes and tender lettuces emerging from the garden.
And that tartness is just so delicious - why not give these lovelies the lemon bar treatment? Sweetened and simmered into a smooth curd, then poured over a simple shortbread crust and baked until rosy, puffed perfection, rhubarb turns from brachiosaurus food to first picnic fare and we’re all the better for it.
Because these bars are absolutely delicious. A balancing act in the best possible way, the buttery shortbread is crisp and just barely sweet, the perfect base for the rosy rhubarb curd to perch upon. The grain-free shortbread is insanely easy, too - just a couple flours, some sugar and melted butter pressed into a pan. While it’s baking, the curd is assembled - first the rhubarb is simmered into syrupy submission, then mixed with eggs and butter until a thick, sweet-tart curd forms. I strain the curd for ultimate smoothness, but if you’re feeling lazy it’s fine to skip. After the two components come together, a final brief stint in the oven puffs and sets the curd. The hardest part, really, is waiting for them to cool.
Which, of course, is harder for some of us than it is for others. I made these during a nap, and the toddler of the house went nuts when he woke up, at first disappointed that they were too warm to dig in, then overjoyed at his after-dinner treat, then quite upset two days later when he learned that his father ate the last one. Luckily for him, grandma and grandpa have one or two stalks left in their patch…
Honeyed Rhubarb Bars
- ¾ cup almond flour (95g)
- ½ cup cassava flour (65g)
- ¼ cup coconut flour (35g)
- ⅓ cup coconut sugar (65g)
- 10 Tbsp butter, melted (140g)
- ½ tsp kosher salt
- 2 ½ cups rhubarb, sliced (285 g)
- ⅔ cup honey (200g)
- 2 Tbsp arrowroot starch
- 2 tsp cream of tartar
- ¼ tsp kosher salt
- 3 whole eggs
- 3 egg yolks
- 2 lemons zested and juiced
- red food coloring (optional)
- 4 Tbsp unsalted butter cubed
- 1/2 cup powdered sugar
- Preheat oven to 350°F with rack in middle of oven. Prepare a 8x8 metal pan with a parchment sling by making two long sheets of parchment paper that are 8 inches wide. Lay the parchment sheets in the pan perpendicular to one another so that they overlap on the bottom. Press the parchment into the pan, creasing along the bottom edges of the pan so that the line the pan. This will make it easy to lift the finished bars from the pan and maintain crisp sides. (If parchment is unavailable you may substitute foil here. Do not use waxed paper.)
- Combine flours, coconut sugar and salt in a bowl. Whisk to ensure even mixing. Add butter and stir to combine, ensuring no dry flour remains. Transfer shortbread mixture to your prepared pan. Using your fingers, pat mixture to a flat, even layer that covers the entire bottom of the pan. Set bowl aside (no need to wash it quite yet). Bake crust until golden brown, 18 to 25 minutes, turning once halfway through to ensure even browning. Crust will be a deep golden at the edges when it is finished.
- while the crust bakes, make the rhubarb puree by mixing the chopped rhubarb, honey, and lemon zest in a small saucepan. Cook over med-low heat until juices start to release from the rhubarb, then increase heat to medium and simmer until the rhubarb falls apart, about 15 min. Using a handheld blender or food processor, puree the rhubarb mixture until very smooth.
- Using the same bowl you used to make the shortbread crust, combine arrowroot starch, cream of tartar, and salt using a whisk. Add in eggs, whisking until no streaks remain and eggs are well-combined. Add in lemon juice. Using a whisk or your handheld blender, mix egg mixture constantly while slowly adding the warm rhubarb puree to it. Going slowly and whisking constantly here is important to prevent your eggs from cooking + curdling. If a brighter pink color is desired, add red food coloring, a couple drops at a time, until the desired color is achieved. Remember to mix completely between additions.
- Transfer filling to the small saucepan you used to make the rhubarb puree. Cook over medium-low heat, stirring constantly, until mixture reaches 160 degrees F and thickens somewhat, 8-12 minutes. Remove from heat and stir in butter until fully melted. Using a fine mesh sieve, strain filling into a clean bowl. Discard whatever does not make it through the sieve. Pour hot filling over your just-baked crust and spread into a single, even layer that reaches all edges. Bake bars until just set (filling will jiggle slightly when shaken and puff gently at the edges) 8-14 minutes. Remove from oven and let cool 45 minutes. Store in fridge until ready to serve.
- Lift bars from pan using the parchment sling and place on a cutting board. Using a chef’s knife or long serrated knife, cut into 4 equal 2-inch strips. Turn bars 90 degrees and cut again to make 2-inch squares. Dust with powdered sugar, if desired.