Preheat oven to 350 degrees.
Lightly coat a 13x9” baking pan with cooking spray or butter.

1. In a small saucepan melt the butter. Simmer butter until it foams and just begins to turn light brown, about 4–5 minutes. Remove from the heat immediately and set aside to cool. (Use caution to avoid burning the butter.)
   
   
2. In a large bowl, sift together the flour, salt, soda and baking powder.
   
   
3. Whisk the warm water, brown sugar, eggs and vanilla into the cooled butter, mixing until smooth.
   
   
4. Pour the butter mixture over the flour and use a sturdy wooden spoon to stir together until combined.
   
   
5. Spread the mixture into the prepared pan. Sprinkle with chocolate chips and toffee pieces or nuts (if desired).
   
   
6. Bake for 30–40 minutes, or until a toothpick inserted into the center comes out clean and the sides start to pull away from the pan. Cool thoroughly before slicing.