Preheat the oven to 325 degrees F. Butter a 9 by 13-inch pan.

Cream together the sugar and softened butter. Stir in the flour and mix well. Add the chocolate syrup, eggs, salt, and vanilla and mix everything well. Pour the batter into the prepared pan. Bake for 25 minutes. Let cool.

For the mint topping: Mix the confectioners' sugar, melted butter, and creme de menthe together until smooth. Let cool slightly and spread over the cooled brownies.

For the chocolate topping: Melt the chocolate chips in the butter and pour over the mint topping. Let the brownies and toppings cool completely and cut into 2-inch squares.