Step 1: Heat the Milk and Cream

1. In a medium saucepan, combine milk and heavy cream.
2. Heat over medium-low until the mixture is hot but not boiling (small bubbles around the edge).
3. Remove from heat and set aside.

Step 2: Mix the Yolks and Sugar

1. In a large bowl, whisk together the egg yolks and granulated sugar until pale and thickened.

Add the flour and cornstarch, whisking until smooth and fully incorporated.

1. Step 3: Temper the Eggs
2. Slowly pour the warm milk mixture into the egg mixture, whisking constantly to prevent curdling.
3. Once combined, pour the mixture back into the saucepan.

Step 4: Cook the Custard

1. Return the saucepan to medium heat.
2. Cook, whisking constantly, until the mixture thickens and begins to bubble (about 5–7 minutes).
3. Once thickened, remove from heat and whisk in the butter and vanilla extract until smooth.

Step 5: Cool the Cream

1. Strain the custard through a fine-mesh sieve into a clean bowl to remove any lumps.
2. Press plastic wrap directly onto the surface to prevent a skin from forming.
3. Let cool to room temperature, then refrigerate for at least 2 hours before using.