Step‑by‑Step Instructions

• Preheat your oven to 350°F (175°C) and grease a square baking dish.
• Whisk together the granulated sugar and all-purpose flour in a mixing bowl.
• Melt unsalted butter and let it cool slightly before mixing it into the dry ingredients.
• Add the egg and vanilla extract to the crust mixture and stir to combine.
• Press the crust mixture into the bottom of the greased baking dish.
• Bake the crust in the preheated oven for 20 minutes until golden brown.
• Heat the milk and heavy cream in a saucepan until simmering.
• In a separate bowl, whisk together the egg yolks, cornstarch, and powdered sugar until smooth.
• Gradually pour the hot milk mixture into the egg yolks, whisking constantly.
• Return the combined mixture to the saucepan and cook over medium heat until thickened.
• Stir in the lemon zest and pour the custard over the cooled crust.
• Cover and chill in the refrigerator for at least 2 hours until set.
• Cut into squares and serve chilled or at room temperature.