Step 1: Prepare the Base
In a medium saucepan, whisk together the sugar, cornstarch, and 2 cups of milk.
Place the saucepan over medium heat and whisk constantly until the mixture becomes hot but not boiling. This helps dissolve the sugar and cornstarch completely.
Step 2: Add Eggs and Remaining Milk
Slowly add the whisked eggs to the hot milk mixture, whisking constantly to prevent curdling.
Gradually pour in the remaining 2/3 cup of milk, continuing to whisk until the mixture is smooth and well combined.
Step 3: Thicken the Custard
Keep whisking over medium heat until the custard thickens to a pudding-like consistency. This should take about 5-7 minutes.
Once thickened, remove the saucepan from the heat.
Step 4: Add Flavor
Stir in the vanilla extract and a pinch of salt to enhance the flavor.
Transfer the custard to a clean bowl or individual serving dishes.
Step 5: Cool and Serve
Let the custard cool to room temperature, then cover with plastic wrap (press it directly onto the surface to prevent a skin from forming).
Refrigerate for at least 2 hours to chill and set completely.