In what the owner hopes is the first of many locations across the country, Toast'N Egg is about to debut at Irving Street and 20th Avenue, serving variations on the popular egg-filled Korean street toasts known as gilgeori."I learned how to make eggs when I was really young," says restaurateur Cyrus Shen, speaking to Eater. "I would add different sauces or seasonings onto the eggs to change up the flavors. When I think back to eating egg toasts,…