Turkish Walnut Baklava From Scratch

Name: Turkish Walnut Baklava From Scratch
Ingredients: 1 egg; 1/2 cup vegetable oil; 1/2 cup water; 1/2 cup milk; 1 tsp baking powder; 3+½ flour; pinch salt; 250 gr. butter (we will melt and take out the foamy part after it); 250 gr. wheat starch (you can use corn starch if you can't find); 350 gr. walnuts (coarsley chopped); 5 cups sugar; 3+½ cups water; 1 small lemon wedge; 1 tsp lemon juice (You can use less syrup first and add more after tasting if needed. The recipe amount is a bit more than enough.)