Preheat the oven to 350 degrees F. Line an 8 inch pan with foil and grease bottom only.
Combine chocolate and oil in a 3 quart saucepan and place over low heat. Stir gently just to melt the chocolate. Pay close attention so the chocolate doesn't burn or boil.
Remove from heat; whisk in sugar, egg, egg white, prune puree, vanilla, and salt until smooth.
Stir in the cocoa powde until fully blended, then stir in the flour. Make sure the batter is not so warm as to melt the chocolate chips, then add about ⅓ cup of chocolate chips (optional, but good!)
Spread batter in prepared pan. Bake until top is firm and a toothpick inserted in center comes out with a few moist crumbs. For me this was between 30 and 35 minutes. Cool completely in pan. Using foil, lift brownies from pan. Cut into rectangles or squares.