In a medium-size heat-safe bowl, place the flour blend, sugar, cocoa powder and salt, and whisk to combine well. Add 1/2 cup of the milk, and then the egg yolks, whisking to combine after each addition. Set the mixture aside.

In a medium-size heavy-bottom saucepan, place the remaining 2 1/2 cups milk and bring to a simmer over medium heat.

Once the milk reaches a simmer, remove the saucepan from the heat and slowly trickle the hot milk into the bowl with the egg and chocolate mixture, whisking constantly to combine.

Pour the whole mixture back into the saucepan and return to the heat. Cook, whisking constantly, over medium-high heat until the whisk leaves a visible trail in the pudding as you whisk it (2 to 3 minutes).

Remove the pan from the heat, add the chopped chocolate, chopped butter, and the vanilla, and stir until the pudding is smooth.

Pour into a large bowl and place plastic wrap directly on the surface of the pudding to prevent it from forming a skin. Set aside to cool.

In a medium saucepan, place the sugar, water, cream of tartar and salt, and whisk together. Cook the mixture over medium-high heat until it reaches the softball stage (240°F on an instant read candy thermometer).

Remove the cooked sugar from the heat, and set it aside to cool briefly. In the bowl of your stand mixer fitted with the whisk attachment (or a large bowl with a handheld mixer), whip the egg whites until soft peaks form. With the mixer on low speed, pour the cooked sugar carefully down the side of the stand mixer bowl.

Add the vanilla extract, and increase the mixer to high speed, and beat until stiff peaks form (5 to 7 minutes).

In 6 small containers, each about 8 ounces in capacity, pour a thick layer of the chocolate pudding, then a thinner layer of the fluff, followed by another layer of chocolate pudding and a large dollop of fluff.

The parfaits can be stored in the refrigerator for 2 days ahead of time.

Top with a graham cracker immediately before serving.