Separate the egg white from the yolk. Beat the egg whites in a small container until stiff.
In another bowl, mix the egg yolks with the milk and fruit juice. Add the mineral water. Mix in the flour, oatmeal, flaxseed and baking powder. Drizzle in some lemon juice and fold in the egg white.
Heat a medium-sized non-stick pan over medium heat and add a little butter. As soon as the pan is hot, pour in the batter and bake covered until the bottom is browned. Turn once and fry until the bottom is baked brown.
Cut the apple into small pieces. Use the spatula to divide the dough into smaller pieces. Add the apple to the pan and leave it on the stove for a while with the lid closed. Turn around from time to time.
Sweeten the yogurt with agave syrup. Arrange the Kaiserschmarrn on a plate and pour the yogurt over it.