What happens if you put a ten day old eg in brownies and eat them?

Eating brownies made with a ten-day-old egg is generally considered safe, as long as the eggs have been properly stored and refrigerated. Eggs typically remain edible for several weeks when refrigerated, and the baking process will further reduce any potential microbial risks. However, it is always best to use fresh eggs whenever possible to ensure the best flavor and quality of your brownies.