Vanilla Dessert Sauce

Heat the milk in a substantial saucepan over low heat, stirring occasionally, until it reaches a gentle boil, approximately 5 minutes.

Combine the remaining milk and cornstarch in a bowl using a sturdy whisk until they form a uniform blend; add sugar and egg yolks, mixing until the mixture is smooth and free of lumps.

Gradually pour the milk-cornstarch mixture into the simmering milk, whisking continuously to prevent lumps from forming; continue cooking, stirring frequently, until the sauce thickens, around 3 minutes.

Retire the saucepan from the heat source and incorporate the vanilla extract into the sauce, stirring gently to combine.

Pass the sauce through a fine-mesh sieve into another bowl to eliminate any residual cornstarch particles. Cover the sauce with a sheet of plastic wrap, ensuring it makes contact with the surface to prevent a crust from forming; allow the sauce to cool to room temperature, approximately 20 minutes.

Transfer the chilled sauce to the refrigerator and refrigerate until it reaches a completely cold state, at least 30 minutes.