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Low-Carb Rhubarb & Custard Tart

5 stars, average of 7 ratings

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This is such a delicious, spring inspired keto dessert to make for a special occasion or just to treat yourself with something indulgent yet light. So here's my take on this classic rhubarb tart made without sugar and flour!

This will be a shows-topping dessert to make for Mother's Day or even Valentine's Day as forced rhubarb isn't just pretty and pink but also available between January and March. When forced rhubarb isn't in season anymore, you can always use field-grown rhubarb which will give a pretty red-green hue to this tart.

We've got our signature Sweet Keto Pie Crust which is sturdy and leakproof, making it the ideal crust for custard fillings. The baked pie crust is then filled with creamy vanilla custard, and topped with tangy ginger and vanilla flavored roasted rhubarb which balances the sweetness of the custard. For extra crunch and flavor you'll want to sprinkle the tart with toasted almond flakes. Simply delicious!

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Hands-on Overall

Serving size 1 slice

Allergy information for Low-Carb Rhubarb & Custard Tart

✔  Gluten free
✔  Nightshade free
✔  Pork free
✔  Avocado free
✔  Coconut free
✔  Fish free
✔  Shellfish free
✔  Beef free

Nutritional values (per serving, 1 slice)

Net carbs5.6 grams
Protein12.7 grams
Fat31.6 grams
Calories361 kcal
Calories from carbs 6%, protein 14%, fat 80%
Total carbs8.9 gramsFiber3.3 gramsSugars2.7 gramsSaturated fat12.6 gramsSodium56 mg(2% RDA)Magnesium75 mg(19% RDA)Potassium374 mg(19% EMR)

Ingredients (makes 8 servings)

Pie crust:
  • 350 g rhubarb, forced for pink or field-grown (12.3 oz)
  • 3 1/2 tbsp granulated granulated Allulose or Erythritol (35 g/ 1.2 oz)
  • 1/2 tbsp grated ginger
  • 1/2 whole vanilla pod or 1/4 tsp vanilla bean powder
  • 2 tbsp flaked toasted almonds, to sprinkle (12 g/ 0.4 oz)


  1. Prepare the Sweet Keto Pie Crust by following instructions in this recipe (including the baking). Make sure to create a good edge so the tart can hold the filling. When done, set aside to cool. Low-Carb Rhubarb & Custard Tart
  2. Prepare the custard. In a small bowl, sprinkle the gelatin over the water and set aside to bloom.
  3. In a bowl whisk the egg yolks and the sweetener until pale and frothy (Allulose is best but other options like Erythritol can be used instead). You can use an electric mixer or a hand whisk.
  4. Place the almond milk, cream and vanilla extract (or split vanilla pod with seeds scraped into the cream) into a saucepan. Bring to a simmer over a medium-high heat. Remove the vanilla (if using whole pod). Low-Carb Rhubarb & Custard Tart
  5. Use a ladle to gradually temper the hot cream mixture into the egg yolk and sweetener mixture. Keep whisking constantly.
  6. When you have added about half of the cream mixture, return everything into the pot with the remaining almond and cream mixture. Cook for about 5 minutes, mixing at all times. Add the bloomed gelatin and stir until fully dissolved. Set aside to cool down to room temperature.
    Note: If the mixture curdles, don't panic. Just blitz with a stick blender until smooth again. Low-Carb Rhubarb & Custard Tart
  7. Pour in the baked pie crust and place in the fridge to set, for about 3 hours. Low-Carb Rhubarb & Custard Tart
  8. To prepare the rhubarb, preheat the oven to 180 °C/ 355 °F (fan assisted), or 200 °C/ 400 °F (conventional).
  9. Cut the rhubarb into about 4 cm (1.5 inch) pieces. Using a sharp knife, cut the vanilla pod lengthwise and scrape the tiny seeds out. Place in a baking tray and add the grated ginger, vanilla seeds and vanilla pod. Evenly sprinkle with Allulose (or granulated low-carb sweetener of choice).
  10. Cover with a foil, place in the oven and bake for 15 minutes. Remove from the oven, shake to combine and cover in the syrup. Remove the foil and return into the oven to bake for another 5 to 8 minutes. The rhubarb should feel tender, not mushy, and it should still keep its shape. When done, remove from the oven and set aside to cool.
    Note: Photo below is from double the amount used in our Roasted Rhubarb recipe. Low-Carb Rhubarb & Custard Tart
  11. Carefully top with the rhubarb pieces. Serve sprinkled with flaked toasted almonds or refrigerate until needed. Low-Carb Rhubarb & Custard Tart
  12. Store in the fridge for up to 4 days. Low-Carb Rhubarb & Custard Tart

Ingredient nutritional breakdown (per serving, 1 slice)

Net carbsProteinFatCalories
Sweet Keto Pie Crust (KetoDiet blog)
2.2 g8.4 g15.5 g179 kcal
Water, still
0 g0 g0 g0 kcal
Gelatin powder, thickening agent, unsweetened
0 g0.8 g0 g3 kcal
Vanilla extract, sugar-free, alcohol-based
0 g0 g0 g2 kcal
Egg yolk, fresh
0.5 g2 g3.4 g41 kcal
Allulose, natural low-carb sweetener
0.4 g0 g0 g2 kcal
Almond milk natural (unsweetened)
0.1 g0.2 g0.4 g4 kcal
Cream, heavy whipping, pouring, full-fat (30-40% fat)
0.8 g0.6 g11.4 g110 kcal
Rhubarb, raw
1.2 g0.4 g0.1 g9 kcal
Allulose, natural low-carb sweetener
0.2 g0 g0 g1 kcal
Ginger root, fresh
0.1 g0 g0 g0 kcal
Vanilla extract, powder (vanilla bean)
0 g0 g0 g0 kcal
Almonds, nuts (flaked, sliced)
0.1 g0.4 g0.8 g9 kcal
Total per serving, 1 slice
5.6 g12.7 g31.6 g361 kcal

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Martina Slajerova
Creator of

Martina Slajerova

I changed the way I ate in 2011, when I was diagnosed with Hashimoto’s, an autoimmune disease that affects the thyroid. I had no energy, and I found it more and more difficult to maintain a healthy weight.

That’s when I decided to quit sugar, grains, and processed foods, and to start following a whole-foods-based ketogenic approach to food.

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