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Keto Rhubarb Custard Pie

This keto rhubarb custard pie pairs a buttery almond flour crust with a creamy, sugar-free custard and tender rhubarb. Bake until the filling is set and lightly golden, then chill for clean, sliceable custard texture.
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Prep Time 25 minutes
Cook Time 50 minutes
cooling 3 hours
Total Time 4 hours 15 minutes
Servings: 8 servings
Course: Dessert
Cuisine: American
Calories: 430
Ingredients Equipment Method Notes

Ingredients
  

For crust
  • 2 cup almond flour
  • 0.25 cup butter, melted
  • 2 tbsp erythritol
  • 1 egg
For filling
  • 3 cup fresh rhubarb, diced
  • 1 cup erythritol (or preferred keto sweetener)
  • 3 eggs
  • 0.25 cup heavy cream
  • 3 tbsp almond flour
  • 1 tsp vanilla extract
  • 0.25 tsp salt

Equipment

  • 1 sheet pan

Method
 

Make the crust
  1. Preheat the oven to 350°F and grease a 9-inch pie plate. Place the pie plate on a sheet pan for easier transfer (visual cue: stable, centered in the oven).
  2. Mix almond flour, melted butter, erythritol, and egg, then press the mixture into the pie plate. Visual cue: compact, even crust layer with no loose gaps.
  3. Bake the crust for 10 minutes at 350°F. Visual cue: edges look set and the surface lightly dries.
Fill and bake
  1. Arrange the diced rhubarb in the baked crust. Visual cue: rhubarb is spread evenly across the bottom.
  2. Whisk together erythritol, eggs, heavy cream, almond flour, vanilla extract, and salt until smooth. Visual cue: glossy custard mixture with no visible almond flour lumps.
  3. Pour the custard mixture over the rhubarb. Visual cue: custard rises and level-pours, covering the rhubarb.
  4. Bake for 40-45 minutes at 350°F until the custard is set and lightly golden. Visual cue: the center jiggles slightly but does not look wet.
Cool and serve
  1. Cool the pie completely for at least 3 hours before slicing. Visual cue: custard firms up fully and the top no longer looks loose.
  2. Refrigerate and serve chilled. Visual cue: slice holds its shape with creamy custard texture.

Notes

For the smoothest custard, whisk until the mixture looks uniform and lump-free before pouring. Store leftovers in the refrigerator for up to 4 days; freeze not recommended for best custard texture. For a lower-fat version, use half-and-half in place of heavy cream (custard will be slightly lighter but still set).