To ensure your vanilla custard reaches the perfect creamy texture for the Strawberry Pastry, begin by mixing cold milk with egg yolks, cornstarch, sugar, and vanilla extract in a separate bowl. This step is crucial as it helps prevent lumps from forming in your custard. After mixing, gradually introduce the heated milk to this mixture, stirring continuously to maintain a smooth consistency. Cook the combined mixture over medium heat while continually stirring until it thickens; this typically takes around 5-10 minutes. Once thickened, remove the custard from the heat and let it cool completely. For an added touch, cover the custard with plastic wrap (directly on the surface) to prevent a skin from forming as it cools.