In a saucepan pour the water and add the sugar. Bring the heat to medium level and let it boil for 20minutes. Before you take it out from the heat, add the squeezed ¼ fresh lemon juice in it and boil 2-3 minutes more. Then set aside until the syrup completely cool as room temperature.
In a bowl; add the room temperature unsalted butter, vegetable oil, whole milk, plain yogurt, semolina and mix them very well. Using a spatula will help you to mix the ingredients well.
Add white flour and baking powder to the mix by using a flour sifter. And then knead the mix very well until all combined.
After making the dough, cover the bowl with stretch film and place it to the refrigerator to rest for10 minutes.
Take the dough from the refrigerator and divide the dough into 20 equal pieces. Make small balls.
Take one of the pieces and flatten it gently in your palm or a clean working surface to give oval shape.
Place the oval-shaped dough piece on to the grater and fill it with grounded walnuts and join the folds at the ends to seal it.
Remove it from the grater and you will see grid pattern on the surface. Place it on a baking tray.
Repeat the same process until all dough balls finish.
Pre-heat oven to 350F (180C).
Bake them 25 minutes. Until they get a golden color.
After they get a golden color, take out the baking tray from the oven and put it on to the kitchen counter and then drizzle the room temperature syrup immediately from the top of pasteries.
Leave it to absorb the syrup for 1 hour.
Remove the pastries from the tray and place them into the deep serving plate and take the remaining syrup from the baking tray and pour evenly from the top of pastries by using a spoon.
Garnish the pastries with ground pistachio.