Mix warm milk, yeast and honey. Leave for 5–10 minutes until foamy.
Add flour, sugar, eggs, vanilla and salt. Knead for 7–10 minutes. Gradually incorporate butter and knead until smooth and elastic.
Cover and rise for 1–1½ hours. Refrigerate for 30–60 minutes.
Divide into 12 pieces of 65–70 g. Shape into balls, place on parchment squares and proof for 45–75 minutes.
Fry at 170–175°C for 1½–2 minutes per side. Drain and cool completely.
Heat milk and vanilla for the pastry cream. Whisk yolks, sugar, cornstarch and salt. Temper with hot milk, return to the saucepan and cook until very thick. Cook for another minute after bubbling, then whisk in butter. Cover the surface and refrigerate until cold.
Brown the butter for the apple filling. Add diced apples, brown sugar, cinnamon and salt. Cook for 6–10 minutes until tender and almost dry. Stir in vanilla and lemon juice. Cool completely.
Fill each donut with 20–25 g pastry cream and 15–20 g apple filling, piping pastry cream first, then apple, then more pastry cream.
Heat sugar, water and glucose syrup until the syrup reaches 150–155°C. Stop stirring once boiling.
Carefully dip the tops of the cool, dry donuts into the pale caramel. Let excess drip off and place on parchment to set.
