Preheat your oven to 325°F. Grease an 8×8 inch metal baking pan thoroughly.
In a medium bowl, whisk together almond flour, brown sugar replacement, cinnamon, and salt. Break up any lumps.
Pour in melted butter slowly and stir with a fork until mixture resembles coarse crumbs that clump together when pressed.
Press the crust mixture firmly into the prepared pan, creating an even layer. Pay extra attention to corners. Bake for 15-20 minutes until edges are golden brown. Let cool completely.
For the filling, pour heavy cream into a medium saucepan. Add powdered erythritol and allulose. Whisk together before heating.
Heat on medium, bringing to a gentle simmer. Whisk frequently for about 20 minutes until reduced by one-quarter and mixture coats the back of a spoon.
Remove from heat. Sprinkle glucomannan over the surface while whisking vigorously to prevent clumps. Add coconut extract and stir.
Fold in shredded coconut until every strand is coated. Spread mixture evenly over the completely cooled crust.
Bake for 15-20 minutes until edges just start browning. The center will still be slightly soft. Remove and let cool completely.
For the chocolate topping, melt chopped chocolate and butter together using microwave (30-second intervals, stirring between) or double boiler method until smooth and glossy.
Pour melted chocolate over cooled coconut layer and spread quickly to edges with an offset spatula.
Refrigerate for 20-30 minutes until chocolate firms completely. Cut into 16 equal bars using a sharp knife, wiping clean between cuts.