Preheat oven to 400º F. Cut out parchment paper to line the bottom of the ramekins or the springform pan. Add the round of parchment paper into the cups or pan, and grease the ramekins or springform pan all the way up the sides of the pan. Set aside.
Into a heatproof bowl, combine dark chocolate, cacao powder, 1 cup of coconut sugar (reserve remaining sugar for meringue), and coconut oil. Pour boiling hot water over the mixture, and stir until the chocolate is melted and a thick, smooth ganache is formed. Note: If the chocolate doesn’t fully melt, put the bowl over a boiling pot on the stove (to make a double boiler) for a couple of minutes to heat the mixture enough to fully melt the chocolate.
Add the egg yolk, almond flour, sea salt, and vanilla extract into the melted chocolate mixture, and stir until a very thick and glossy cake batter is formed.
Add the egg whites to a stand mixer bowl with a whisk attachment. Add cream or tartar, and whip egg whites on high until soft peaks form. Add 1/4 cup of coconut sugar, and continue mixing until stiff peaks form. You should be able to turn the bowl upside down without the egg whites moving out of place.
Add 1/4 of the egg whites into the chocolate cake batter, and fold in. Continue folding until no streaks of egg whites remain. This loosens up the batter so the next addition stays more airy.
Add the remaining whites, and gently fold into the batter. Use a rubber spatula to gently pull cake batter from the bottom of the bowl, folding onto the top. Continue until the mixture is uniform and no white streaks remain. Tip: Egg whites not mixed in well will cause uneven rising of the soufflés.
Divide the batter evenly between the 4 ramekins, or add to the prepared pan.
Bake soufflés for 15-17 minutes for a molten center, or 20 minutes for a more evenly baked chocolate soufflé cake.
Allow soufflés to cool for about 10 minutes prior to serving. Dust the top of the cake with powdered sugar or cacao powder. Cakes can be served in the ramekins. If desired, run a knife around the edges of the ramekins and turn the ramekin over into your hand, and then place the cake directly on a plate.Note: If baking in a springform pan, let the cake cool for 10-15 minutes prior to slicing it to serve.