Place parchment paper on a cooking sheet. Mix together the salt, baking soda and flour.
In a separate bowl whisk the egg whites. Add the cocoa powder, sugar, vanilla, milk and oil. Whisk the items together until the mixture is smooth. Whisk in the flour mixture. Stir in ½ of the chocolate chips.
Pour the brownie mixture evenly onto the parchment paper. Spread the batter over top of it and sprinkle the rest of the chocolate chips on top.
Let the bark cook for about 15 minutes.
Remove from the oven and cut into squares, but do not separate the squares.
Place the bark back into the oven for about 5 minutes. Remove from the oven and let cool before breaking the bark into pieces.