Place farmer’s cheese, eggs, sugar, semolina, salt, lemon zest, and vanilla in a bowl and stir until smooth. Then stir in the raisins and set aside.
Pre-heat oven to 400°F. Line a baking sheet with a piece of parchment paper.
On top of a silicone mat or kitchen towel, roll out a sheet of puff pastry dough to a rectangle. Brush the dough with some of the melted butter.
Spread the filling onto about ⅓ of the dough on the long side, leaving a border on the edges.
Gently pull the dough up and over the filling, using the towel to help lift it.
Continue use the towel to roll up the strudel all the way.
Carefully transfer the strudel to the baking sheet, making sure the seam is on the bottom. Brush the top of strudel with more of the melted butter.
Bake 10 mins; remove from oven and brush with more of the melted butter. Rotate and bake for another 10 mins; remove again and brush with the remaining butter. Repeat at 5 min intervals until top crust is nicely browned. (~30-35 mins in total).
While the strudel is in the oven, combine ½ packet of vanilla pudding powder with 1 cup cold milk.
Cut strudel into pieces, dust with powdered sugar and serve with vanilla sauce.