Peel and core the apples. Cut them into small pieces. Mix with the raisins (optional), sugar, and cinnamon.
Microwave the apple mixture for 2 minutes to soften, or skip this step if using softer apple varieties like Golden Delicious.
Add 3 drops of butter-vanilla flavor to the milk. Brush the yufka leaves with the milk mixture. Place one quarter of the apple mixture on a yufka leaf and roll up, brushing with milk as you roll.
Place the 4 rolled-up turnovers in a baking dish and brush with milk.
Bake at 175°C (347°F) on convection setting for about 20 minutes, until golden brown. If the turnovers look dry during baking, brush with milk again.