• 2 sticks (16 Tbsp.) butter, plus more for buttering the pan and the wax paper

  • 8 ounces (240 gr.) good-quality dark chocolate (couverture)

  • 4 eggs

  • ½ tsp. salt

  • 1 cup brown sugar

  • 1 cup sugar

  • 2 tsp. Mastiha powder

  • 2 tsp. vanilla extract

  • 1 cup flour

  • ½ cup chopped walnuts or ¾ cup whole walnuts, optional

  1. Butter a 13x 9-inch( 33 x 23 cm) baking pan and spread butter onto a large piece of wax paper. Preheat the oven to 350˚F (180˚C). In a double boiler over simmering water, melt the butter and chocolate together.Let the mixture cool slightly. In a large bowl or mixer beat the eggs. Beat in the salt, both sugars, Mastiha and vanilla until combined.

  2. Beat in the chocolate mixture. Fold in the flour until blended. If you use chopped walnuts, add them into the mixture as well. Pour the mixture in the prepared baking pan. If you use whole walnuts place them on top of the mixture. Bake the brownie for 35 to 40 minutes, until its surface is shiny and cracked on the surface. Place the pan on a rack and let it cool.