Heat the oven and prep the pan. Set the oven to 350°F (175°C).
Lightly grease a 9-inch pie dish.
Make the crust. In a bowl, mix almond flour, cocoa, granulated sweetener, and salt. Stir in melted butter and vanilla until the mixture resembles damp sand and clumps when pressed.
Press and bake. Press the mixture evenly into the bottom and up the sides of the pie dish. Dock the base with a fork.
Bake for 10–12 minutes until set and fragrant. Cool completely.
Bloom the gelatin. Sprinkle gelatin over 2 tablespoons cold water in a small bowl. Let sit 5 minutes to soften.
Start the custard base. In a medium saucepan, whisk heavy cream, almond milk, powdered sweetener, salt, and cocoa powder.
Warm over medium heat until steaming, not boiling.
Melt in the chocolate. Add chopped unsweetened chocolate and whisk until smooth and glossy.
Temper the yolks. In a separate bowl, whisk egg yolks. Slowly drizzle in 1/2 cup of the hot chocolate mixture, whisking constantly. Pour the tempered yolks back into the saucepan.
Thicken gently. Cook over low heat, stirring constantly with a spatula, until the mixture thickens slightly and coats the back of the spoon (about 170–175°F).
Do not boil.
Add gelatin and finish. Remove from heat. Stir in the bloomed gelatin until fully dissolved. Whisk in butter and vanilla until silky.
Cool and pour. Let the filling cool for 10–15 minutes, stirring occasionally to prevent a skin.
Pour into the cooled crust and smooth the top.
Chill to set. Cover loosely and refrigerate at least 4 hours, preferably overnight, until firm.
Whip the topping. Beat heavy cream, powdered sweetener, and vanilla to soft peaks. Spread or pipe over the chilled pie. Add chocolate shavings if you like.
Slice and serve. Use a sharp knife warmed under hot water and wiped dry for clean slices.