1. Prepare Pan: 

Grease the sides and bottom of an 8-inch (20cm) square pan with vegetable oil.
Line parchment paper, grease the parchment as well. Set aside.
2. Prepare Syrup: 

In a large saucepan, combine sugar, 270ml of water, and lemon juice.
Set over medium heat. Allow to boil until the sugar dissolves.
Reduce the heat to low and let simmer until the mixture reaches 235-240F (112-115C) (soft ball stage). Remove from heat and set aside.
3. Prepare Cornstarch Mixture: 

In a separate saucepan, combine cornstarch and 2¼ cups (540ml) water, stirring until no lumps remain.
Place over medium heat, stir constantly until the mixture begins to boil and has a glue-like consistency.
4. Combine Syrup and Cornstarch Mixture: 

Gradually stir in the syrup to the cornstarch mixture, stirring constantly for about 5 minutes.
Reduce the heat to low and let simmer for about 45-60 minutes, stirring frequently, until lightly golden.
5. Add Flavors and Pour: 

Stir in the rose water, food coloring, and vanilla extract.
Pour the mixture into the prepared pan. Spread evenly and allow to cool for at least 4 hours.
6. Coat Turkish Delight: 

In a big dish, mix powdered sugar and cornstarch.
Sprinkle some of the mixture over a clean surface.
Turn the dough over and cut into little squares.
Coat each square with the cornstarch mixture.
Enjoy your homemade Turkish Delight!