Preheat your oven to 350°F (175°C). In a food processor, combine almond flour, coconut flour, powdered allulose, and melted unsalted butter. Pulse until mixed, then add 1 large egg, blending until the dough pulls away from the sides. If it seems dry, add a teaspoon of water. Shape the dough into a disc, wrap in plastic, and chill in the fridge for 30 minutes.

After chilling, roll out the dough on a lightly floured surface until it fits your tart pan. Carefully transfer the crust inside and press it into the edges. Prick the bottom with a fork to prevent bubbling, then bake for 10-12 minutes until golden brown.

In a heat-safe bowl, whisk together eggs, egg yolks, freshly squeezed lemon juice, powdered allulose, and heavy cream. Set the bowl over a pot of simmering water. Whisk constantly for about 15 minutes, until thickened.

Gradually add cubed unsalted butter to the filling while whisking to melt and combine. Continue whisking until smooth and creamy.

Once your crust is baked and cooled, pour the lemon filling into the tart shell. Smooth the top with a spatula and let it cool to room temperature before refrigerating to set completely for about 2 hours.

After cooling, slice your Creamy Keto Lemon Tart and serve chilled, optionally garnished with whipped coconut cream or fresh berries.