Preheat the oven to 400 degrees F. Lightly butter a 9-inch springform pan. For the cake: Sift the flour, cocoa, and baking powder together. In a mixing bowl, whisk the egg yolks with the sugar until the mixture is pale in color. Stir in the butter. Fold in the dry ingredients and mix until thoroughly incorporated. In an electric mixer, beat the egg whites, salt and cream of tartar until stiff peaks form. Fold the white into the chocolate mixture. Pour the batter into the springform pan and bake for 35 minutes. Allow the cake to cool and remove the sides of the pan. Slice the cake into 4 equal layers. Leave the bottom layer in the pan and reattach the sides of the pan. For the pudding: Melt chocolate in a double boiler. Remove the double boiler from the heat and whisk in the egg yolks. In a sauce pan, bring the cream and sugar up to a boil. Whisk the cream into the chocolate mixture. Fold in the pecans and vanilla. Spread a quarter of the chocolate pudding over the first layer and top with another layer of the cake. Continue to layer the pudding and cake until the cake is completed. Let the cake sit for 2 to 3 hours to allow the cake to absorb the pudding. For the sauce: In a sauce pan, bring the cream and Tia Maria to a boil with the vanilla bean. Cover the pan and remove from the heat, and set aside to infuse the cream for 15 minutes. In a mixing bowl, whisk the eggs while gradually adding the sugar. Whisk the cream into the egg mixture. Pour back into the sauce pan and bring the sauce up to a simmer. Cook the sauce until it coats the back of the spoon, about 8-10 minutes. Strain and cool. Whisk in the coffee. Spoon the sauce in the middle of the plate. Place a piece of the cake in the center of the sauce. Garnish with the whipped cream, powdered sugar, and broken chocolate pieces.
Adapted from Stephan Pyles', The New Texas Cuisine.