Melt the butter in a small saucepan or in the microwave. In a medium bowl, mix together the melted butter, almond flour, and granulated sweetener until a crumbly dough forms. Add the egg and mix again until fully incorporated. Line the bottom of your pie dish with baking parchment paper or grease it with a little extra butter if you prefer.

Roll or press the almond flour pie crust dough between two sheets of baking paper, or simply use your hands or the back of a cup to press it evenly into the prepared pie dish. Use a fork to make little holes all over the pie crust to prevent it from puffing during baking. Bake the crust in a preheated oven at 180°C/350°F for about 10 minutes, until just golden. Remove from the oven and set aside.

In a small saucepan, heat the heavy cream over medium heat until it is just below boiling—do not let it bubble. In another bowl, whisk together the eggs, egg yolks, and sweetener until the mixture is pale and fluffy, then stir in the lemon zest and lemon juice. Slowly pour a little of the warmed cream into the egg mixture, whisking constantly to prevent the eggs from curdling. Gradually add the rest of the cream, whisking all the time. Pour the combined mixture back into the saucepan and heat it gently, stirring continuously, until the lemon curd thickens to a custard-like consistency. For extra zing, I sometimes add a bit more lemon juice to taste.

Once the keto lemon curd is as thick as custard, pour it onto the baked pie crust (from Step 2), spreading it out evenly. Bake the filled pie at 180°C/350°F for 10 minutes to set the filling. Remove from the oven and let it cool slightly while you prepare the meringue.

Wipe a large mixing bowl with kitchen paper to ensure it is free from any grease, which helps the egg whites whip up properly. Add the egg whites, granulated sweetener, and vanilla flavoring to the bowl. Using an electric mixer, whisk the mixture until soft peaks form. Gently spread or pipe the meringue over the slightly cooled lemon curd pie, creating decorative peaks with a spoon if desired. I like to give the meringue a rustic look with a few extra swirls on top!

Bake the pie with the meringue topping at 180°C/350°F for 10–15 minutes, or until the meringue is set and golden on top. Let the pie cool before slicing and serving. Enjoy your keto lemon meringue pie!