In a double boiler, add the unsweetened chocolate and almond butter. Place over medium-low heat and stir occasionally until completely melted.
While the chocolate/almond butter is melting, sift the erythritol and salt into a small bowl. Set aside.
When the chocolate/almond butter is completely melted and smooth, stir in the vanilla paste, butter flavor and stevia extract.
Toss in the sifted erythritol and stir together (the chocolate will seize, that's totally fine). Keep the mixture over the heat for a couple more minutes while stirring/folding. Make sure all the erythritol is dissolved and incorporated thoroughly. It should look like the picture down below.