To prepare, pour sugar into a large Mason jar or other large jar. Add cocoa, nuts, baking soda, and salt. Spoon flour on top and press down. Seal jar.
Instructions for Recipe Card:
To make brownies, dump mix into a large bowl. Stir in 3/4 cup melted unsalted butter and then 4 eggs. Spread batter in a lightly greased 13- x 9-inch or 11- x 8-inch pan. Bake at 350 F for 25 to 30 minutes. Cool at room temperature 20 minutes. Refrigerate 30 minutes and then cut.
Recipe by Baker Street at https://bakerstreet.tv/2011/11/brownies-in-a-jar/