Found this recipe, although it used normal cooked egg whites, so I thought I would make the cookies but using salted egg whites instead.
They actually turned out ok and you don't really taste the saltiness. Only thing is that you will see that my cookies are a bit smashed up. I rolled them into balls and then like other cookies, I thought they would expand out, but they didn't and when I tried one, it was a little soft in the centre. So, while they were still hot from the oven, took a fork and pushed them down, hence the ugly appearance!
1/2 cup unsalted butter, cold (113 gms)
1 1/3 cups all-purpose flour
1/2 teaspoon salt (No need as using salted egg whites)
1/4 teaspoon baking soda
1/4 cup sugar
1/4 cup brown sugar
whites from 1 1/2 hard-boiled eggs, broken into small pieces ( I just chopped them up)
1/2 teaspoon vanilla extract
2 tablespoons whole milk
1/2 cup semisweet chocolate chips
Preheat oven to 350 F, 170 deg C
Using an electric mixer, beat butter on high speed until you have a bowl full of little butter crumbles.
Mix in flour until completely combined with the butter.
Mix in rest of the ingredients.
Mix in the vanilla extract and milk.
Fold in the chocolate chips.
Roll dough into small balls (or big ones if you like bigger cookies) and place on a cookie sheet lined with parchment or a Silpat. Remember to squash them down as they will not expand. This way, you get nice crispy cookies.Bake for 20 minutes or until the bottoms are slightly browned.