Prepare ingredients for proper preparation of homemade eclairs. Sift the flour. Cut the butter into cubes and leave at room temperature. Wash the apples, peel them and grate them on a coarse grater. Wash the eggs and separate the yolks at 3. Turn on the oven to preheat to 200 degrees.
Prepare the dough for homemade eclairs. Combine milk and water in a saucepan, add salt, sugar and butter. Place on the fire and bring to a boil. Then reduce the heat and add flour. Stir the flour with a spatula until it boils and the mixture becomes thick and homogeneous. Evaporate excess liquid by constantly stirring the dough. Remove the pan from the heat and cool the dough slightly. Add the eggs into the dough one at a time, stirring them in with a spatula. Place the finished dough into a piping bag.
Form and bake the eclairs. Line a baking sheet with parchment and form eclairs by squeezing them out of a pastry bag. Bake in a preheated oven for 20-25 minutes. Eclairs should be browned, dry and hollow inside.
Make apple custard. Place the grated apples in a saucepan, add powdered sugar and place on the fire. Bring the mixture to a boil and cook for 20 minutes. In a separate bowl, combine the yolks, vanilla and cornstarch, stir. Pour the yolks with starch into the boiling applesauce and brew the cream for 1 minute, stirring vigorously. Remove the cream from the heat and cool until warm. Then add butter to it and stir until smooth.
Fill the eclairs with apple cream. Cut each eclair in half or make a hole in the side or bottom and fill with a small amount of apple cream. Let the dessert soak and serve.
Before serving, drizzle homemade eclairs with a small amount of apple jam.