In a medium saucepan over medium heat, bring whipping cream to a simmer. In a medium bowl, whisk egg yolks with sweetener and salt until well combined.
Slowly whisk about half of the hot cream into the yolks to temper, then stir the yolk/cream mixture back into the remaining cream in the saucepan and cook until thick and glossy, about 3 to 4 minutes, whisking continuously.
Remove from heat and whisk in butter and vanilla. Let cool to lukewarm.
In a medium saucepan over low heat, melt butter. Stir in cocoa powder and sweetener, and then slowly whisk in the egg.
Cook, stirring constantly, until mixture thickens. Remove from heat and stir in vanilla, almond flour, shredded coconut and nuts. Press crust into a 9x9 or 8x8 square pan evenly and refrigerate until firm.
Beat cream cheese and butter until smooth. Beat in the cooled pastry cream until well combined, then beat in additional powdered sweetener. Spread filling over crust and refrigerate until firm, at least one hour.
Combine chopped chocolate and butter in a heatproof bowl set over a pan of barely simmering water. Stir until melted and smooth. Spread over filling and let set.