Low-Carb Rhubarb and Custard Tart
A sophisticated keto-friendly tart featuring silky vanilla bean custard set with gelatin and topped with roasted rhubarb pieces. The sweet pie crust provides structure while allulose or erythritol keeps carbs minimal. Tangy roasted rhubarb with warming ginger contrasts the creamy custard base. Serve chilled for afternoon tea, dinner parties, or as an elegant keto dessert. This version combines gelatin-set custard with roasted rather than raw rhubarb for deeper flavor and texture contrast.
Ingredients
- 1 recipe Sweet Keto Pie Crust
- 3 tbsp water (45 ml)
- 2 tsp gelatin powder
- 1 whole vanilla pod or 2 tsp sugar-free vanilla extractvanilla extractsubstitute givenvanilla
medium
- 6 large egg yolks
- ⅓ cup granulated Allulose or Erythritol (67 g/ 2.4 oz)Monk fruit sweetener1:1ketosweetener
high
- 1 cup unsweetened almond milk (240 ml/ 8 fl oz)
- 1 cup heavy whipping cream (240 ml/ 8 fl oz)
- 12 ⅓ oz g rhubarb, forced for pink or field-grown (12.3 oz)strawberries or raspberries350gFull guide →
- 3 ½ tbsp granulated granulated Allulose or Erythritol (35 g/ 1.2 oz)Monk fruit sweetener1:1ketosweetener
high
- ½ tbsp grated ginger
- ½ whole vanilla pod or 1/4 tsp vanilla bean powdervanilla extractsubstitute givenvanilla
medium
- 2 tbsp flaked toasted almonds, to sprinkle (12 g/ 0.4 oz)
Instructions
- 1
Prepare and bake Sweet Keto Pie Crust according to recipe, ensuring good edge to hold filling, then cool.
- 2
Bloom gelatin in water in small bowl.
- 3
Whisk egg yolks with sweetener until pale and frothy.
- 4
Heat almond milk, cream, and vanilla in saucepan to simmer over medium-high heat, then remove vanilla pod if using.
- 5
Gradually temper hot cream into egg mixture using ladle while whisking constantly.
- 6
Once half cream is incorporated, return mixture to pot with remaining cream and almond milk.
- 7
Cook 5 minutes while stirring, then add bloomed gelatin and stir until fully dissolved.
- 8
Cool custard to room temperature, blitzing with stick blender if curdled.
- 9
Pour custard into baked crust and refrigerate 3 hours to set.
- 10
Preheat oven to 350°F fan or 400°F conventional.
- 11
Cut rhubarb into 1 ½" pieces, scrape vanilla pod seeds, and place on baking tray with ginger and vanilla seeds.
- 12
Sprinkle rhubarb evenly with sweetener, cover with foil, and bake 15 minutes.
- 13
Shake tray to combine with syrup, remove foil, and bake another 5-8 minutes until tender but holding shape.
- 14
Cool rhubarb, then arrange on custard tart and sprinkle with toasted almonds.
Tips
Temper egg yolks gradually to avoid scrambling; use a ladle and whisk constantly for safety.
Roast rhubarb until just tender to maintain structure and color; overcooking creates mush.
If custard curdles during cooking, immediately blitz with immersion blender until smooth.
Good to Know
Refrigerate in airtight container up to 4 days. Do not freeze due to gelatin-custard texture breakdown.
Prepare pie crust up to 2 days ahead. Custard filling can be made 1 day ahead and poured into crust on serving day. Roast rhubarb up to 8 hours ahead and top tart just before serving.
Serve chilled directly from refrigerator. Accompany with unsweetened whipped cream or Greek yogurt if desired. Best served within 2 hours of topping with rhubarb to maintain tart texture.
Common Mistakes
Do not skip tempering step to avoid scrambled egg yolks in custard
Do not overcook rhubarb to avoid mushy texture loss
Do not pour hot custard into crust to prevent crust softening
Substitutions
Dairy-Free Swaps
General Alternatives
high
FAQ
Can I make this without a pie crust?
Yes, pour cooled custard into small serving glasses and refrigerate 2 hours, then top with roasted rhubarb. Skip crust preparation entirely for a simpler keto custard cup dessert.
What if my custard curdles during cooking?
Remove from heat immediately and blend with immersion blender until completely smooth. Return to heat briefly if needed to fully dissolve gelatin, then cool again before pouring into crust.
How long can I keep the assembled tart?
Store refrigerated up to 4 days in airtight container. Do not freeze; gelatin-set custard loses texture when thawed. Top with almonds just before serving for best crispness.