you don't. don't cut. ever. i have and it messed up my life so badly. you think after one cut you will be done, just to see what it's like. but it's not like that. it's an addiction. one cut lead's...
Either refrigerate the entire pan thoroughly or freeze lightly for about 1/2 hour, or cool your brownies. Once the fat in the brownies solidifies, they will be easy to cut cleanly. Just don't try to...