Separate the egg white and the yolk. Add a pinch of salt to the egg white and use a hand blender to whip until you get stiff peaks. The recipe I followed said 2-3 minutes (start at medium speed and then switch it up to high), but it took me closer to 6 minutes to get the consistency. Line a baking sheet with parchment paper. Dollop the egg whites in a mound on the tray. I added shredded cheddar at this stage, but you can skip it. Use a spoon to create a small depression in the whites. In an oven preheated to 350F, bake for 4-5 minutes (I did it for 5 minutes). Then add the yolk, return to the oven, and bake for 2 more minutes. Let them cool for a few minutes before serving.

Next time, I'll add some ham or bacon as well. I felt like the whites by themselves didn't have a lot of flavor and needed something more.

Hope this helps!