Step 1

Preheat oven to 350 degrees F. Grease an 8 inch metal pan and line with foil. Grease bottom oil with extra butter or spray with cooking spray.

Step 2

Begin melting the butter in a small saucepan over medium heat. When it is about halfway melted, reduce heat to low and add the chocolate chips. Melt the chips, then stir in the cocoa powder and 1/3 cup of the sugar (the brown, if using two kinds). Remove from heat and stir until smooth.

Step 3

In a mixing bowl, using a handheld electric mixer, beat together the eggs, the other 1/3 cup of sugar, salt and vanilla.

Step 4

Stir the melted chocolate mixture into the egg mixture, then stir in the tapioca flour.

Step 5

Spread batter in pan and bake for 25-27 minutes or until top appears set.

Step 6

Let cool at room temperature for several hours or let cool slightly at room temperature and finish cooling in the refrigerator.

Step 7

Lift from pan and cut into squares.