Fit a stand mixer with the whisk attachment. Make sure that bowl is clean and completely dry before placing the egg whites in. Beat on low speed, gradually increasing to high and beating until light and stiff peaks form. You can also use a hand mixer or good old wire whisk!
In a separate, small bowl combine the caramel sauce, sweetened condensed milk, flour, and vanilla extract. Whisk until and completely combined and smooth.
Use a rubber spatula to fold the caramel and milk mixture into the egg whites. As you fold, scrape down the sides of the bowl, repeatedly folding the mixture over itself to evenly incorporate the caramel and milk into the egg whites without deflating them. Repeat until no streaks of unmixed egg whites remain.
Last, fold in the coconut.
Use a 2 ounce cookie scoop to scoop out the macaroons 2 inches apart onto a cookie sheet lined with parchment paper.
Bake the cookies at 325° for 12 - 14 minutes or until the macaroons are brown on the top flakes of coconut and sound hollow in the middle.
If desired, you can add chocolate to the macaroons. To do this, melt the chocolate chips with the coconut oil in the microwave at 30 second intervals until smooth in consistency. Dip the bottoms into the chocolate or simply drizzle over.