rhubarb strawberry custard tart with low carb gluten-free crust

Rhubarb Strawberry Tart (Low Carb & Gluten-free)

Rhubarb Strawberry Tart is a gluten-free, low carb recipe that lets rhubarb shine in a vanilla-rhubarb custard studded with fresh strawberries all encased a gluten-free almond flour crust. The perfect celebration of summertime!

Rhubarb is a vegetable? What? Says who? It belongs in pies, crumbles, tarts, and jams. It has to be a fruit. It’s hard to admit when we are wrong, but I guess I am. It’s almost rhubarb season, so of course, I’m starting to think about all the recipes I can cook up. On my trip to England in April, I found a rhubarb-infused gin. That is obviously happening. Some how, some way. But until I start making my own bootleg, bathtub gin, I’ll stick to enjoying rhubarb baked goods. While Strawberry Rhubarb Pie is the quintessential favorite, there are a number of other ways to celebrate this vegetable. It still doesn’t sound right, does it?

Strawberry Rhubarb Tart Recipe Inspiration

This recipe is an adaptation from Dorie Greenspan’s latest cookbook, Everyday Dorie. I received the book as a Christmas gift, and while it is full of beautiful photos and alluring recipes, my dietary choices limited me from trying most of them. So, like any good kitchen fiend, I’ve started playing with adapting for my diet.

a slice of rhubarb strawberry custard tart

As I flipped through the book, the picture of the “Mostly Rhubarb Tart” was utterly stunning and immediately drew me in. I’ve never really experimented with rhubarb, and for good reason; I’ve had one too many pieces of overly sugary strawberry rhubarb pie to last me a lifetime and to turn me off to the dessert combination almost indefinitely. But this picture was too good to pass up.

Rhubarb is the star in this dessert. Given it’s bitter nature, I hoped that this recipe would yield something less cloying. In many strawberry rhubarb recipes, the rhubarb is a secondary flavor and often overwhelmed by sugar. Strawberries are used sparingly here, just to give a little pop of sweetness. I kept Ms. Greenspan’s custard recipe as is, but reduced the sugar, as my taste buds have changed.

It took a few tries to make this work, especially in the absence of a wheat-based tart shell. Almond flour on it’s own gave me a very soft and moist crust. After it sat for a few hours, the texture was almost unpleasant. I was determined to keep this recipe as low carb as possible, so I next tried the addition of some coconut flour, tapioca flour (it’s so little, it’s negligible), and xanthan gum. This blend gave a crunchy, flaky crust that really does resemble a traditional tart.

The resulting Rhubarb Strawberry Tart is a keeper, especially when you can highlight the beautiful color of fresh rhubarb and strawberries.

a slice of rhubarb strawberry tart
Rich rhubarb-vanilla custard surrounds chunks of rhubarb and slices of fresh strawberries.

How to make Low Carb Rhubarb Strawberry Tart

Let the crust rest. The tart shell absolutely has to rest in the refrigerator. You want the butter to firm back up, but you also want to ensure that the flours have time to absorb some of the moisture that is inherent in almond flour. If you bake the crust right after assembly, you will not get a firm crispy texture. Add the custard component into the mix and you can probably make some inferences about what will happen: soggy bottom. Bleh.

Give the rhubarb time to macerate. Macerate, there’s a fun new word for you. To macerate is basically the equivalent of soaking in a liquid. In order for the rhubarb syrup to form, you need to give the ingredient some quality soaking time. I normally let this sit for about 1-2 hours. Given that you are using erythritol, you will need a bit more time. I’ve found that it is not as responsive as refined sugar when it comes to pulling out the natural sugars and breaking down the rhubarb. The longer the soak, the more intense the rhubarb custard will be in the end.

Pay attention to baking your crust. You will want to pre-bake the crust right after pulling out of the refrigerator for about 10 minutes. Once I fill it, I will check about every 10 minutes during the baking process to avoid burnt edges. Once the edges start to look dark, I cover with tin foil and allow the custard to continue to set and cook. This will likely be about somewhere in the middle of the cook time. Because almond and coconut flour burn much faster, skipping this step will likely end in some very dark brown and rather unappetizing edges on your tart.

Other Low Carb Dessert Recipes You’ll Love

Rhubarb Strawberry Tart
Yield: 8 servings

Rhubarb Strawberry Tart

Prep Time: 40 minutes
Cook Time: 40 minutes
Chill Crust: 1 hour
Total Time: 2 hours 20 minutes

A vanilla-rhubarb custard studded with fresh rhubarb pieces covered with sliced strawberries in a gluten-free and low carb almond flour crust. The perfect celebration of summer!

Ingredients

Filling

  • 2 1/2 cups rhubarb, sliced into 1/2 inch pieces
  • 1/2 cup erythritol, divided
  • 1/2 cup heavy cream
  • 1 large egg
  • 1 egg yolk
  • 1 tsp vanilla extract
  • 10-12 strawberries, sliced

Crust

  • 1 cup blanched almond flour
  • 1/4 cup coconut flour
  • 2 tbsp tapioca flour
  • 1/4 tsp xanthan gum
  • 1/4 cup erythritol
  • 1 large egg
  • 4 tbsp salted butter, chilled, cut into small pieces

Instructions

  1. For the crust, combine all dry ingredients in a food processor. Pulse to combine. Add egg and butter. Pulse again until dough mixture forms.
  2. Press dough mixture into a 9" tart pan with clean fingers. Start with the bottom and work your way up the sides of the pan, forming an even crust. Use about 3/4 of the dough for the bottom and the remaining 1/4 for the sides. Poke bottom with a fork several times to prevent rising.
  3. Place tart crust on a small baking tray, cover loosely with parchment and put into the refrigerator for 1 hour. This is a critical step -- do not skip.
  4. While crust refrigerates, make the rhubarb syrup. In a medium mixing bowl, combine rhubarb and 1/4 cup erythritol. Stir and set aside for at least 1 hour. A syrup will begin to form as the rhubarb macerates. Stir occasionally during that time.
  5. Remove crust from refrigerator. Pre-bake for 10 minutes in a 350 degree oven. While it is baking, finish making the custard.
  6. Drain rhubarb, reserving the syrup for the custard. In a medium mixing bowl, combine heavy cream, eggs, vanilla, remaining erythritol, and rhubarb syrup. Whisk to combine.
  7. Remove the tart crust from the oven. Line bottom of the crust with rhubarb pieces, arranging neatly and evenly. Pour custard over top. Carefully arrange sliced strawberries on top.
  8. Cook for 40-50 minutes in a 375 degree oven. Check every 10-15 minutes to avoid burnt crust edges. If edges get too dark, cover only the sides with foil and leave the custard exposed. Custard should be just set, but not cracked.
  9. Serve slightly warm, room temperature, or chilled. Refrigerate any leftovers.

Notes

Custard portion adapted from Dorie Greenspan's book, "Everyday Dorie"

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4 Comments

  1. OMG!! This was amazing!! I have never cooked (or baked) with erythritol before so I was a little concerned about a strange “sweetener” taste but boy was I wrong! No strange or overpowering flavor at all. Just delicious buttery-ness ( I used ghee) complimented by the sweet tartness of the strawberries and rhubarb. What a great dessert! My entire family loved it!

  2. Hope Cressman

    Hi! I just discovered you via a google search for rhubarb and I want to make this recipe but have a question about the erythritol (wondering if I can use the powdered icing sugar variety?) cause that’s what I have on hand. It doesn’t specify in the recipe above and I’m not sure the granulated version is interchangeable?

    • Hi Hope! I do that all the time, actually. Erythritol is not on sale much where I now live, so I use up whatever I have on hand first before stocking up. The volume is a little different though. 1/4 cup granulated will be about 1/3 powdered, so maybe reduce the overall measurement. I tend not to like things sweet, so maybe you won’t even notice the difference. Let me know how it goes! I’d love to be able to share that with readers!

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