Preheat oven to 150°C (300°F) and line a baking sheet with parchment paper.
Whisk egg whites with cream of tartar and salt in a clean bowl until stiff peaks form.
Blend the egg yolks with softened cream cheese until smooth in a separate bowl.
Gently fold the egg yolk mixture into the egg whites until just combined.
Spoon the mixture onto the baking sheet to form 4 equal rounds.
Bake for 20 minutes until golden and set, then cool slightly.
While the cloud bread bakes, whisk together 2 eggs, milk, salt, and pepper.
Melt butter in a nonstick skillet over medium heat and gently scramble the eggs until just set.
Assemble sandwiches by layering scrambled eggs, cheese, and turkey bacon or vegetarian alternative between two pieces of cloud bread.
Garnish with fresh herbs if desired and serve warm.