Heat oven to 375 degrees. In a medium bowl, whisk starch, gum, salt, baking powder, pudding; set aside. In a small bowl combine cream, and vanilla with fork until combined; set aside.

In standing mixer, cream butter and sugar at medium-high speed until light and fluffy, 3 to 4 minutes. Scrape down bowl with rubber spatula. With mixer running at medium speed, add the cream and beat until incorporated, about 30 seconds. Scrape down bowl. With mixer running at low speed, add starch mixture until the dough is formed, about 1 to 2 minutes. ( If too dry add an extra tablespoon of heavy cream. )

In a well greased 9 x 13 pan, press the dough into an even layer. Bake until light golden brown, about 20 to 25 minutes. Place the base in the fridge for 15 minutes to cool.

Meanwhile, prepare the topping: Melt the butter, cocoa powder, and 1/2 cup of the sugar in the top of a double boiler over simmering water.

Whisk to combine baking mix, salt and baking powder in medium bowl; set aside.

Add egg to mixer with a whisk attachment. Whip until frothy. Gradually add the remaining half cup of sugar, 1 tablespoon at a time, taking 4 minutes to complete. Gradually whisk in the chocolate mixture. Add coffee and vanilla. Fold in the dry ingredients.

Spread the chocolate mixture evenly over the cooled base.

Bake until the top rises and forms a very thin crust, about 20 minutes. The center will drop as it cools. Warning -- it will look like terrible when you take it out of the oven -- gooey and weird. No worries -- when it cools it becomes the most decadent chewy brownie top. Cool completely on a rack before cutting.