Position rack in bottom one-third of oven and preheat to 325 degrees. Line 8x8x2-inch pan with foil pressing firmly against the sides of the pan and leaving a 2 inch overlap. Coat foil with non-stick spray.
Melt butter over medium heat. Cook until it stops foaming and browned bits form on the bottom of pan, stirring often, about 5 minutes. Remove from heat and immediately add sugar, cocoa, water, vanilla and salt. Stir to blend. Cool for 5 minutes. Add eggs to hot mixture, one at a time, beating vigorously after each egg. When mixture looks thick and shiny, add flour and stir until completely blended. Stir in walnuts. Transfer to pan.
Bake for 25 minutes. Cool in pan on a rack. Using foil overhang, lift brownies out of pan. Cut into 16 brownies.

