- 1/2 cup butter
 - 2 (1 ounce) squares unsweetened chocolate, chopped
 - 2 eggs
 - 1 cup white sugar
 - 1 teaspoon vanilla extract
 - 3 tablespoons matzo meal
 - 1/2 cup potato starch
 - 1/2 teaspoon salt
 - 1/2 cup chopped walnuts (optional)
 - 1/2 cup semisweet chocolate chips (optional)
 
- Preheat the oven to 350 degrees F (175 degrees C). Grease an 8×8 inch square pan.
 - Melt the butter in a small saucepan over medium heat. Remove from the heat and stir in the unsweetened chocolate. Set aside.
 - In a medium bowl, beat the eggs and sugar with an electric mixer for about 5 minutes. Reduce the speed to low, and pour in the chocolate and butter, then stir in the vanilla. In a separate bowl, stir together the matzo meal, potato starch and salt. Use a spoon to stir into the chocolate mixture until well blended. Mix in the walnuts or chocolate chips if using. Pour into the prepared pan and spread evenly.
 - Bake for 25 minutes in the preheated oven, until the brownies are dry on top and begin to pull away from the sides.