Wash the apple and cut it into quarters. Peel and remove the seed pod. Cut each quarter lengthwise in half, and then cut crosswise into fairly thin slices.

In a bowl, place flour, baking soda, and a pinch of salt. Mix thoroughly.

In a tall container, such as a blender jar, crack the egg. Beat with a mixer or a kitchen whisk into a fluffy mass.

Add sweetener and mix. Then add milk and a few drops of food-grade vanilla flavor. Mix again.

Combine the egg mixture with the dry ingredients. Mix and mash thoroughly with a spoon until you get a uniform batter (without lumps).

Add apple pieces to the batter and mix.

Heat a non-stick pan. Melt small amounts of butter on the pan to fry a few pancakes at a time (spread the butter evenly over the entire surface). Put about 1 tablespoon of batter for each pancake - make sure that each pancake contains apple slices. Fry several pancakes at the same time. Fry all the pancakes until golden brown, about 1.5 minutes per side.

Transfer the finished pancakes to a plate and optionally sprinkle with calorie-free "powder" just before eating (crushed erythritol or stevia, etc.). Eat warm or cold.